@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;450;500;550;600;650;700&family=Manrope:wght@500;600;650;700;750;800&display=swap');
:root{--ink:#102345;--muted:#536481;--blue:#1464ed;--line:#e3eaf4;--paper:#fff;--bg:#f4f7fc;--soft:#edf4ff;--shadow:0 5px 20px #203c6410;--radius:19px;color-scheme:light;font-family:'DM Sans',Arial,sans-serif;color:var(--ink);background:var(--bg)}*{box-sizing:border-box}body{margin:0;line-height:1.55}button,input,select,textarea{font:inherit}button,a,input,select,summary{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:default;opacity:.55}a{color:inherit;text-decoration:none}a:hover{color:var(--blue)}button,a{ -webkit-tap-highlight-color:transparent}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #f4a72d;outline-offset:4px}h1,h2,h3,h4{font-family:Manrope,Arial,sans-serif;line-height:1.2;letter-spacing:-.035em;margin:0}h1{font-size:46px;font-weight:800}h2{font-size:24px;font-weight:800}h3{font-size:18px;font-weight:800}p{margin:10px 0 16px}small,.muted{color:var(--muted)}.icon{width:21px;height:21px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}.skip{position:fixed;top:-100px;left:15px;background:var(--ink);color:white;z-index:99;padding:12px}.skip:focus{top:10px}.site-header{height:76px;background:var(--paper);border-bottom:1px solid #dce5f077;position:sticky;top:0;z-index:20}.nav-inner{max-width:1280px;padding:0 30px;margin:auto;height:100%;display:flex;align-items:center;gap:44px}.brand{display:flex;gap:13px;align-items:baseline;white-space:nowrap;font-size:24px;font-weight:800;font-family:Manrope,sans-serif;letter-spacing:-1px}.brand em{font:italic 23px Georgia,serif;color:#314a72;letter-spacing:0}.desktop-nav{display:flex;gap:29px;align-items:center;font-size:14px;font-weight:700}.desktop-nav a{padding:25px 0}.desktop-nav a.active{color:var(--blue);box-shadow:inset 0 -3px var(--blue)}.header-search{margin-left:auto;display:flex;align-items:center;gap:9px;color:var(--muted);background:#f0f3f9;border-radius:30px;padding:10px 16px;border:0;min-width:210px;text-align:left;font-size:13px}.header-search .icon{width:16px;height:16px}.header-help{font-size:14px;font-weight:700}.icon-button{border:0;background:transparent;padding:8px;display:flex;color:var(--ink);border-radius:10px}.shell{max-width:1280px;margin:auto;padding:22px 30px 52px}.hero{position:relative;isolation:isolate;min-height:420px;border-radius:21px;overflow:hidden;display:flex;align-items:center;padding:48px;color:white;background:#184967}.hero>img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;z-index:-2}.hero:after{content:'';position:absolute;inset:0;background:linear-gradient(90deg,#08253ede 0%,#08253e95 45%,#08253e05 100%);z-index:-1}.hero-content{width:100%;max-width:790px}.hero h1{max-width:570px;font-size:clamp(36px,4.5vw,55px);letter-spacing:-.045em;line-height:1.05}.hero p{font-size:17px;max-width:610px;margin:18px 0 25px}.search-form{display:flex;align-items:center;gap:12px;background:white;color:var(--ink);padding:6px 7px 6px 20px;border-radius:36px;box-shadow:0 5px 20px #071c3525}.search-form input{background:none;border:0;min-width:0;flex:1;padding:11px 0;outline-offset:0}.search-form .primary{border-radius:26px;min-height:43px;padding:9px 25px}.primary{border:1px solid var(--blue);background:var(--blue);color:white;border-radius:10px;padding:11px 20px;font-weight:700;display:inline-flex;align-items:center;justify-content:center;gap:8px}.primary:hover{background:#074fc7;color:white}.secondary{border:1px solid #ccd9eb;background:var(--paper);color:var(--ink);border-radius:10px;padding:10px 17px;font-weight:650;display:inline-flex;align-items:center;justify-content:center;gap:8px}.secondary:hover{background:var(--soft);color:var(--blue)}.popular{display:flex;gap:8px;align-items:center;flex-wrap:wrap;font-size:12px;margin-top:18px}.popular strong{margin-right:5px}.popular a{border-radius:30px;padding:6px 13px;background:#e2f2ff33;backdrop-filter:blur(8px);border:1px solid #ffffff25}.popular a:hover{background:white;color:var(--ink)}.subject-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin:22px 0 32px}.subject-card{position:relative;border-radius:19px;background:white;box-shadow:var(--shadow);overflow:hidden;min-height:208px;display:flex;flex-direction:column}.subject-image{height:123px;width:100%;object-fit:cover}.subject-card:first-child .subject-image{object-position:50% 45%}.subject-body{padding:19px 23px 17px;background:var(--paper);border-radius:20px 20px 0 0;margin-top:-19px;position:relative;flex:1}.subject-body h2{font-size:28px}.subject-body p{font-size:14px;max-width:85%;margin:7px 0 0;color:var(--muted);line-height:1.5}.circle-arrow{position:absolute;right:22px;top:23px;display:grid;place-items:center;background:var(--blue);color:white;width:32px;height:32px;border-radius:50%}.subject-card.science .circle-arrow{background:#079674}.section-top{display:flex;align-items:center;justify-content:space-between;gap:16px;margin:30px 0 18px}.section-top>a{font-size:13px;color:var(--blue);font-weight:700;display:flex;align-items:center;gap:9px}.section-top .icon{width:18px}.discovery-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:19px}.discovery-card{border-radius:16px;overflow:hidden;box-shadow:var(--shadow);background:var(--paper);border:1px solid #e4ebf355;transition:transform .16s,box-shadow .16s}.discovery-card:hover{transform:translateY(-4px);box-shadow:0 10px 27px #203c6420}.discovery-card>img{width:100%;height:157px;object-fit:cover;display:block}.discovery-body{padding:15px 16px 17px}.discovery-body h3{font-size:16px;line-height:1.3;letter-spacing:-.025em;min-height:42px}.discovery-body>p{font-size:12px;margin:6px 0 11px;color:var(--muted)}.card-meta{display:flex;align-items:center;gap:6px;font-size:11px;color:var(--muted)}.card-meta .icon{width:14px;height:14px}.colour-icon{background:#edf1ff;color:#7740d3;border-radius:12px;width:44px;height:44px;display:grid;place-items:center;flex-shrink:0}.colour-icon.green{background:#e2f8ee;color:#009673}.colour-icon.blue{background:#e5f0ff;color:#1464ed}.colour-icon.orange{background:#fff1da;color:#b56d00}.help-strip{padding:23px;background:linear-gradient(120deg,#f0edff,#eaf2ff);border-radius:20px;margin:31px 0}.help-strip h2{font-size:20px;margin-bottom:17px}.tool-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.tool{display:flex;align-items:center;gap:12px;background:var(--paper);border-radius:15px;padding:17px 13px}.tool strong{font-size:12px;display:block}.tool small{font-size:11px;display:block;margin-top:3px}.explore-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.explore-card{background:var(--paper);border-radius:14px;box-shadow:var(--shadow);overflow:hidden}.explore-card img{height:120px;width:100%;object-fit:cover;display:block}.explore-card div{padding:12px 14px}.explore-card h3{font-size:15px}.explore-card p{font-size:12px;margin:5px 0 0;color:var(--muted)}.teacher-note{margin:35px 0 0;padding-top:22px;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:35px;font-size:13px;color:var(--muted)}.teacher-note strong{color:var(--ink)}.teacher-note p{margin:5px 0}.site-footer{max-width:1220px;margin:auto;border-top:1px solid var(--line);padding:24px 0 30px;display:flex;justify-content:space-between;gap:20px;font-size:12px;color:var(--muted)}.site-footer>div{display:flex;gap:20px}.bottom-nav{display:none}.breadcrumb{display:flex;gap:10px;align-items:center;font-size:12px;color:var(--muted);margin-bottom:20px}.breadcrumb a:hover{text-decoration:underline}.lesson-banner{position:relative;overflow:hidden;border-radius:20px;padding:30px 32px 55px;background:linear-gradient(90deg,#edf5ff 35%,#e8f3ff44),url('/assets/alpine-sunrise.webp') right 46%/cover;min-height:205px}.lesson-banner h1{font-size:46px}.lesson-banner p{max-width:610px;margin:10px 0 0;font-size:16px}.lesson-layout{margin:-20px 20px 0;position:relative;background:var(--paper);border:1px solid #e7edf6;border-radius:18px;box-shadow:var(--shadow);padding:0 23px 26px}.lesson-tabs{display:flex;justify-content:space-between;gap:5px;padding:0 0 0;border-bottom:1px solid var(--line);overflow-x:auto;scrollbar-width:thin;position:sticky;top:76px;z-index:8;background:var(--paper);border-radius:18px 18px 0 0}.lesson-tabs a{display:flex;align-items:center;justify-content:center;gap:8px;padding:18px 8px;font-size:12px;font-weight:700;white-space:nowrap;border-bottom:3px solid transparent}.lesson-tabs .icon{width:19px;height:19px}.lesson-tabs a:hover,.lesson-tabs a.active{color:var(--blue);border-bottom-color:var(--blue)}section[id],div[id]{scroll-margin-top:151px}.lesson-block{border-radius:16px;margin-top:22px;padding:24px;background:#edf5ff}.lesson-block.lavender{background:#f3efff}.block-heading{display:flex;align-items:flex-start;gap:13px;margin-bottom:19px}.step-badge{border-radius:9px;min-width:34px;height:34px;display:grid;place-items:center;background:var(--blue);color:white;font-weight:700;box-shadow:inset 0 0 8px #ffffff40}.lavender .step-badge{background:#9455ec}.block-heading h2{font-size:22px;margin:3px 0 7px}.block-heading p{font-size:14px;margin:0;max-width:740px}.learn-grid{display:grid;grid-template-columns:1fr 260px;gap:28px}.key-ideas{background:#ffffffb3;padding:19px;border-radius:13px;font-size:13px}.key-ideas h3{font-size:14px}.key-ideas ul{padding-left:18px;margin:10px 0 0}.key-ideas li{margin:7px 0}.numberline{width:100%;max-width:760px;height:auto;overflow:visible;display:block}.numberline text{font-family:'DM Sans',sans-serif;font-size:15px;fill:var(--ink)}.numberline .blue-text{fill:#175edf}.numberline .red-text{fill:#c34522}.example-grid{display:grid;grid-template-columns:1.55fr 1fr;gap:16px}.example-box{border:1px solid #ffffff;background:#ffffffb8;border-radius:13px;padding:18px}.eyebrow{font-size:11px;text-transform:uppercase;letter-spacing:.08em;font-weight:750;color:var(--blue);margin-bottom:8px}.example-box h3{font-size:15px;color:#6440ad;letter-spacing:0}.equation{font-size:28px;font-weight:750;font-family:Manrope,sans-serif;letter-spacing:-.03em;margin:15px 0 18px}.example-box p{font-size:13px;margin:9px 0}.example-controls{display:flex;gap:8px;flex-wrap:wrap;margin:14px 0}.small-button{padding:8px 12px;border:1px solid #d6dfee;border-radius:8px;background:var(--paper);color:var(--ink);font-size:12px;font-weight:600}.small-button[aria-pressed=true]{background:var(--blue);color:white;border-color:var(--blue)}.solution{border-top:1px solid #ddd7f4;margin-top:16px;padding-top:13px;font-size:14px}.keep-going{margin:26px 0 6px}.keep-going h2,.related-section h2,.real-world h2{font-size:19px;margin-bottom:15px}.path-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.path-card{border:1px solid #e0eafa;border-radius:12px;background:#f8fbff;padding:15px;display:flex;gap:9px}.path-card b{background:#e0edff;color:var(--blue);width:23px;height:23px;display:grid;place-items:center;border-radius:50%;font-size:12px;flex-shrink:0}.path-card strong{font-size:12px;display:block}.path-card small{display:block;font-size:11px;margin-top:5px}.details-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.detail-panel{border:1px solid var(--line);border-radius:16px;padding:24px;margin-top:22px}.detail-panel h2{font-size:21px;margin-bottom:15px}.detail-panel h3{font-size:16px;margin:20px 0 8px}.detail-panel p,.detail-panel li{font-size:14px}.math-rule{padding:12px 15px;background:var(--soft);border-radius:10px;font-weight:700;margin:13px 0}.notice{background:#fff6e5;color:#78561d;padding:13px 16px;border-radius:12px;font-size:13px}.interactive-panel{background:#f2f7ff;border-radius:17px;padding:25px;margin-top:24px}.interactive-panel h2{font-size:23px}.controls{display:flex;gap:14px;flex-wrap:wrap;align-items:end;margin:18px 0}.field{display:flex;flex-direction:column;gap:6px;font-size:13px;font-weight:650}.field input,.field select{border:1px solid #bdcce0;background:var(--paper);color:var(--ink);border-radius:9px;padding:10px 12px;min-height:44px;width:105px}.field select{width:auto}.hint{background:#fff7e8;padding:13px 16px;border-radius:10px;color:#76551b;font-size:14px}.feedback{padding:12px 0;min-height:45px;font-weight:600;font-size:14px}.feedback.correct{color:#08784c}.feedback.incorrect{color:#a23d2f}.practice-card{background:var(--paper);border:1px solid #dce5f3;border-radius:14px;padding:24px;margin-top:16px}.practice-top{display:flex;justify-content:space-between;align-items:center;font-size:12px;color:var(--muted)}.progress-track{background:#e3eaf6;height:6px;border-radius:10px;margin-top:12px;overflow:hidden}.progress-track span{display:block;background:var(--blue);height:100%;width:0;transition:width .2s}.practice-form{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.practice-form input{border:1px solid #b6c8e0;border-radius:10px;padding:10px 14px;width:160px;color:var(--ink);background:var(--paper)}.related-section,.real-world{margin:27px 0}.related-links{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.related-links a{border:1px solid var(--line);border-radius:10px;padding:14px 12px;font-size:12px;font-weight:650;display:flex;gap:8px;background:#fff}.related-links .icon{width:18px;height:18px;color:var(--blue)}.context-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.context-card{background:#f8fbff;border:1px solid var(--line);border-radius:12px;padding:17px}.context-card .context-number{font-size:25px;letter-spacing:-1px;font-weight:750;color:var(--blue)}.context-card h3{font-size:14px;margin:8px 0}.context-card p{font-size:12px;margin:0}.resource-section{margin:30px 0}.resource-section h2{font-size:22px;margin-bottom:7px}.resource-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:11px;margin-top:17px}.resource{display:flex;gap:13px;align-items:center;border:1px solid var(--line);background:var(--paper);padding:16px;border-radius:12px;font-size:13px}.resource strong{display:block}.resource small{display:block;font-size:11px;margin-top:4px}.resource .icon{color:var(--blue)}details{background:transparent;border:0;padding:12px 0;border-radius:0;margin-top:10px}summary{cursor:pointer;font-weight:700;font-size:14px}details p{font-size:14px;margin-bottom:0}.dialog{border:1px solid var(--line);border-radius:20px;padding:0;width:min(700px,calc(100% - 32px));max-height:85vh;color:var(--ink);background:var(--paper);box-shadow:0 25px 90px #142a5555}.dialog::backdrop{background:#071a3d77;backdrop-filter:blur(5px)}.dialog-head{display:flex;align-items:center;justify-content:space-between;padding:20px 24px;border-bottom:1px solid var(--line)}.dialog-head h2{font-size:20px}.dialog-body{padding:24px}.dialog .search-form{background:var(--bg);box-shadow:none;border:1px solid var(--line)}.results{margin-top:17px}.result{display:block;padding:14px;border-bottom:1px solid var(--line);border-radius:8px}.result strong{display:block;font-size:15px}.result small{font-size:12px}.result:hover{background:var(--soft)}.collection-header{padding:30px 0}.collection-header p{max-width:680px;color:var(--muted)}.unit-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:17px}.unit-card{background:var(--paper);padding:24px;border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow)}.unit-card h2{font-size:20px;margin:12px 0}.unit-card p{font-size:13px;color:var(--muted)}.unit-card .icon{color:var(--blue)}.article{max-width:830px;margin:auto;background:var(--paper);padding:35px;border-radius:20px}.article>p,.article li{font-size:17px;line-height:1.8}.article>img{width:100%;max-height:320px;object-fit:cover;border-radius:15px;margin:25px 0}.article h2{font-size:25px;margin:28px 0 15px}.article .eyebrow{margin-top:5px}.editor-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px}.editor label{display:block;font-size:13px;font-weight:700;margin:17px 0 7px}.editor input,.editor textarea{width:100%;padding:12px;border:1px solid #b9cae2;background:var(--paper);color:var(--ink);border-radius:9px}.editor textarea{min-height:95px}.editor-actions{display:flex;gap:12px;flex-wrap:wrap;margin:25px 0}.editor-preview{border:1px solid var(--line);border-radius:15px;padding:25px;background:#edf4ff}.dark{--ink:#edf4ff;--muted:#b3c0d4;--paper:#13243e;--bg:#0d192b;--line:#30415e;--soft:#223957;color-scheme:dark}.dark .header-search{background:#21324d;color:var(--muted)}.dark .brand em{color:#a4bbdf}.dark .lesson-banner{background:linear-gradient(90deg,#142840 20%,#14284077),url('/assets/alpine-sunrise.webp') right center/cover}.dark .lesson-block,.dark .interactive-panel{background:#1a304c}.dark .lesson-block.lavender{background:#30264c}.dark .key-ideas,.dark .example-box{background:#172941;border-color:#35435f}.dark .numberline text{fill:var(--ink)}.dark .help-strip{background:#242d4b}.dark .path-card,.dark .context-card{background:#172c48;border-color:#344563}.dark .related-links a{background:var(--paper)}.dark .editor-preview{background:#1a304c}.dark .example-box h3{color:#ccb3ff}.dark .notice,.dark .hint{background:#443617;color:#ffe3a9}.dark .feedback.correct{color:#68e0ac}.dark .feedback.incorrect{color:#ffada2}[hidden]{display:none!important}@media(min-width:1500px){.shell{padding-top:28px}.hero{min-height:447px}}@media(max-width:1050px){.nav-inner{gap:25px}.header-search{min-width:140px}.desktop-nav{gap:20px}.hero{padding:36px;min-height:390px}.learn-grid{grid-template-columns:1fr 230px;gap:15px}.tool{padding:14px 10px;gap:8px}.tool .colour-icon{width:35px;height:35px}.discovery-card>img{height:135px}.resource-grid{grid-template-columns:1fr 1fr}.path-card{padding:12px}.lesson-layout{margin:-20px 10px 0;padding:0 18px 22px}.lesson-tabs a{font-size:11px;gap:6px}.site-footer{margin:0 30px}.brand{font-size:21px}.brand em{font-size:21px}}
@media(max-width:760px){.site-header{height:66px}.nav-inner{padding:0 20px;gap:13px}.brand{font-size:20px;gap:9px}.brand em{font-size:19px}.desktop-nav,.header-help{display:none}.header-search{margin-left:auto;min-width:0;padding:10px;background:transparent}.header-search span{display:none}.shell{padding:16px 18px 35px}.hero{min-height:340px;padding:30px 24px;border-radius:17px}.hero h1{font-size:39px;max-width:470px}.hero p{font-size:14px;max-width:380px;margin:16px 0 21px}.popular{font-size:11px;gap:7px}.popular a{padding:5px 10px}.search-form{padding-left:14px;gap:9px}.search-form input{font-size:13px}.search-form .primary{padding:9px 19px}.subject-grid{gap:14px;margin:17px 0 26px}.subject-image{height:112px}.subject-body{padding:16px}.subject-body h2{font-size:24px}.subject-body p{font-size:12px;max-width:100%;padding-right:0}.circle-arrow{right:14px;top:17px;width:26px;height:26px}.circle-arrow .icon{width:18px}.subject-body h2{padding-right:25px}.section-top h2{font-size:20px}.section-top{margin-top:26px}.discovery-grid{grid-template-columns:1fr 1fr;gap:14px}.discovery-card>img{height:160px}.tool-grid{grid-template-columns:1fr 1fr}.tool{padding:14px}.help-strip{padding:19px}.explore-grid{grid-template-columns:1fr 1fr;gap:14px}.teacher-note{flex-direction:column;gap:12px}.site-footer{padding-bottom:95px;margin:0 20px;flex-direction:column;gap:10px}.bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;z-index:25;background:var(--paper);padding:8px 15px calc(9px + env(safe-area-inset-bottom));border-top:1px solid var(--line);justify-content:space-around;box-shadow:0 -3px 17px #1428450b}.bottom-nav a{display:flex;align-items:center;flex-direction:column;gap:4px;font-size:10px;min-width:58px;color:var(--muted)}.bottom-nav .active{color:var(--blue)}.bottom-nav .icon{width:22px;height:22px}.lesson-banner{padding:23px 23px 44px;min-height:210px}.lesson-banner h1{font-size:38px}.lesson-banner p{font-size:14px;max-width:440px}.breadcrumb{font-size:11px;margin-bottom:15px}.lesson-layout{margin:-20px 0 0;padding:0 13px 20px}.lesson-tabs{top:66px;justify-content:flex-start;gap:12px}.lesson-tabs a{padding:15px 8px;min-height:55px}.learn-grid{grid-template-columns:1fr}.key-ideas{padding:16px;font-size:12px}.key-ideas ul{display:grid;grid-template-columns:1fr 1fr;gap:0 20px}.example-grid{grid-template-columns:1fr}.lesson-block{padding:18px;margin-top:16px}.block-heading h2{font-size:20px}.block-heading p{font-size:13px}.path-grid{grid-template-columns:1fr 1fr}.details-grid{grid-template-columns:1fr;gap:0}.detail-panel{margin-top:15px;padding:20px}.related-links,.context-grid{grid-template-columns:1fr 1fr}.resource-grid{grid-template-columns:1fr 1fr}.resource{padding:13px;font-size:12px;gap:9px}.resource .icon{width:19px}.unit-grid{grid-template-columns:1fr 1fr}.collection-header h1{font-size:36px}.article{padding:24px}.editor-grid{grid-template-columns:1fr}.editor-preview{position:static}.interactive-panel{padding:20px}section[id],div[id]{scroll-margin-top:139px}}
@media(max-width:430px){.shell{padding:12px 14px 27px}.nav-inner{padding:0 17px}.hero{padding:28px 21px;min-height:350px}.hero h1{font-size:34px}.hero p{font-size:13px}.popular a:nth-last-child(-n+2){display:none}.popular{margin-top:14px}.search-form input{font-size:12px}.subject-image{height:101px}.subject-body{padding:15px 13px}.subject-body h2{font-size:22px}.subject-body p{font-size:11px}.circle-arrow{right:11px;top:15px;width:23px;height:23px}.section-top h2{font-size:18px}.section-top>a{font-size:11px;white-space:nowrap}.discovery-card>img{height:120px}.discovery-body{padding:12px}.discovery-body h3{font-size:14px;min-height:36px}.discovery-body>p{font-size:11px}.card-meta{font-size:10px}.help-strip{padding:16px}.help-strip h2{font-size:17px}.tool-grid{gap:9px}.tool{padding:12px 9px;gap:8px}.tool strong{font-size:11px}.tool small{font-size:10px}.tool .colour-icon{width:30px;height:35px;border-radius:9px}.tool .icon{width:19px}.explore-card img{height:100px}.lesson-layout{padding:0 10px 17px}.lesson-banner{padding:22px 19px 44px}.lesson-block{padding:16px}.block-heading{gap:10px}.block-heading h2{font-size:18px}.block-heading p{font-size:12px}.step-badge{min-width:30px;height:30px}.key-ideas ul{display:block}.key-ideas li{margin:5px 0}.numberline text{font-size:17px}.resource-grid{grid-template-columns:1fr}.resource{font-size:13px}.unit-grid{grid-template-columns:1fr}.context-card{padding:13px}.path-card{padding:11px;gap:7px}.path-card strong{font-size:11px}.interactive-panel{padding:17px}.controls{gap:9px}.field input{width:85px}.field{font-size:12px}.field select{max-width:135px}.practice-card{padding:18px}.practice-form input{width:110px}.primary,.secondary{font-size:13px}.teacher-note{font-size:12px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}@media print{header,.bottom-nav,.lesson-tabs,.site-footer,.interactive-panel,.editor-actions{display:none!important}.shell{padding:0;max-width:none}.lesson-banner{background:none;min-height:0;padding:0 0 25px}.lesson-layout{margin:0;border:0;padding:0;box-shadow:none}.lesson-block,.detail-panel{break-inside:avoid}body{background:white;color:black}.hero{color:black;background:white}.hero img,.hero:after{display:none}}
.editor-resource-row{display:grid;grid-template-columns:1fr 1.5fr 130px 80px;gap:10px;margin:10px 0}.editor-resource-row select{border:1px solid #bdcce0;border-radius:9px;padding:10px;color:var(--ink);background:var(--paper);min-width:0}.editor-resource-row input{margin:0;min-width:0;font-size:12px}.sr-label{font-size:13px}@media(max-width:760px){.editor-resource-row{grid-template-columns:1fr 120px}.editor-resource-row input:nth-child(2){grid-column:1/3;grid-row:2}.editor-resource-row select{grid-column:2;grid-row:1}.editor-resource-row button{grid-column:2}}
@media(max-width:430px){.hero{background:transparent;color:var(--ink);min-height:0;padding:22px 9px 15px;border-radius:0;overflow:visible}.hero>img,.hero:after,.hero p,.hero .popular{display:none}.hero h1{font-size:34px;max-width:310px;line-height:1.1;margin-bottom:20px}.hero .search-form{background:#eaf0f8;box-shadow:none;padding:5px 6px 5px 14px}.dark .hero .search-form{background:#243653}.subject-grid{margin:15px 0 23px}.subject-card{min-height:155px}.subject-image{height:115px}.subject-body{padding:13px 12px 14px;border-radius:14px 14px 0 0;margin-top:-18px}.subject-body p{display:none}.subject-body h2{font-size:21px}.circle-arrow{top:13px}.discovery-grid{grid-template-columns:1fr;gap:12px}.discovery-card{display:grid;grid-template-columns:105px 1fr;border-radius:13px;box-shadow:0 3px 13px #203c640a}.discovery-card>img{height:116px;width:105px}.discovery-body{padding:13px 14px}.discovery-body h3{min-height:0;font-size:15px;line-height:1.3}.discovery-body>p{margin:6px 0;font-size:11px}.section-top h2{font-size:18px}.section-top{align-items:baseline}.section-top>a{font-size:11px}.explore-card div{padding:12px}.explore-card h3{font-size:13px}}
.icon-button{min-width:44px;min-height:44px;align-items:center;justify-content:center}.header-search{min-height:44px}@media(max-width:900px) and (min-width:761px){.header-search{min-width:44px;width:44px;padding:12px}.header-search span{display:none}.nav-inner{gap:23px}.header-help{margin-left:auto}}@media(max-width:430px){.numberline text{font-size:24px}#interactive-line text{font-size:31px}#example-line text{font-size:25px}.header-search{min-width:36px;width:36px}.nav-inner{gap:8px}}
.mobile-numberline{display:none}@media(max-width:430px){.wide-numberline{display:none}.mobile-numberline{display:block}.mobile-numberline .numberline text{font-size:19px}#interactive-line text,#example-line text{font-size:24px}}
.hero .search-form{color:#102345;color-scheme:light}.hero .search-form input{color:#102345}.dark .section-top>a,.dark .eyebrow{color:#91bfff}.dark .numberline .blue-text{fill:#91bfff}.dark .numberline .red-text{fill:#ffb6a4}.dark .numberline path[stroke="#203e67"]{stroke:#b3c8e2}.dark .numberline path[stroke="#2162e8"]{stroke:#91bfff}.dark .numberline path[stroke="#c34522"]{stroke:#ffb6a4}
/* Focused learning system */
.section-kicker{font-size:11px;font-weight:750;text-transform:uppercase;letter-spacing:.12em;color:#557394;margin-bottom:9px}.unit-hero{background:linear-gradient(105deg,#edf5ff 45%,#e9f2ffad),url('/assets/alpine-sunrise.webp') center/cover;border:1px solid #dfe9f7;border-radius:22px;padding:34px 38px;display:grid;grid-template-columns:1fr 240px;gap:35px;align-items:center}.unit-hero h1{font-size:58px;letter-spacing:-.055em;margin:8px 0 12px}.unit-hero p{max-width:650px;font-size:17px;color:#465f80}.unit-buttons{display:flex;gap:12px;margin-top:23px}.hero-math{display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:18px}.hero-math>span,.hero-math>strong{border-radius:19px;background:#ffffffa6;display:grid;place-items:center;width:61px;height:78px;color:#1a64d6;font:650 43px Manrope,sans-serif;box-shadow:0 6px 24px #194d8c0c}.hero-math strong{color:#183b63;transform:translateY(-10px)}.hero-math small{color:#547296;font-size:11px;font-weight:600;margin-top:5px}.topic-directory{margin:32px 0}.topic-card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:17px}.topic-card{border:1px solid #e1e9f5;border-radius:17px;padding:23px;background:var(--paper);box-shadow:0 4px 17px #193e6806;transition:transform .15s,box-shadow .15s;display:flex;flex-direction:column;align-items:start}.topic-card:hover{transform:translateY(-3px);box-shadow:0 10px 24px #193e6814}.topic-mark{font:700 17px Manrope,sans-serif;letter-spacing:-.02em;background:#edf4ff;color:#2466c2;border-radius:10px;padding:8px 12px;margin-bottom:17px;min-width:88px;text-align:center}.topic-card:nth-child(3n+2) .topic-mark{color:#6852b3;background:#f1edfb}.topic-card:nth-child(3n) .topic-mark{color:#147c69;background:#eaf7f2}.topic-card h3{font-size:20px;line-height:1.25}.topic-card p{color:var(--muted);font-size:13px;line-height:1.65;margin:10px 0 21px;flex:1}.topic-link{display:flex;align-items:center;gap:8px;font-size:12px;font-weight:700;color:var(--blue)}.topic-link .icon{width:16px;height:16px}.topic-progress{font-size:10px;margin-top:10px;color:var(--muted)}.topic-progress:empty{display:none}.rule-check{background:#eef0fd;border:1px solid #e4e6f4;border-radius:20px;padding:27px;display:grid;grid-template-columns:1fr 1.5fr;gap:25px;margin:35px 0}.rule-check h2{font-size:24px;max-width:300px}.rule-check>div>p{font-size:14px;color:var(--muted)}.rule-comparison{display:grid;grid-template-columns:1fr 1fr;gap:13px}.rule-comparison>div{background:var(--paper);padding:20px;border-radius:13px}.rule-comparison span{color:var(--muted);font-size:12px}.rule-comparison strong{display:block;font:750 21px Manrope,sans-serif;margin:10px 0}.rule-comparison p{font-size:12px;margin:9px 0}.rule-comparison a{font-size:12px;font-weight:700;color:var(--blue)}.unit-help{background:var(--paper);border:1px solid var(--line);padding:25px 28px;border-radius:17px;margin:28px 0}.unit-help h2{font-size:22px}.unit-help p{font-size:14px;color:var(--muted);margin-bottom:0;line-height:1.8}.unit-help a,.text-link{color:var(--blue);font-weight:650}.resource-accordion{padding:22px}.resource-accordion summary{font-size:18px;letter-spacing:-.025em}.resource-accordion summary span{font-size:12px;float:right;color:var(--muted);font-weight:500}.resource-search-label{display:flex;align-items:center;gap:15px;font-size:13px;margin:23px 0}.resource-search-label input{border:1px solid var(--line);background:var(--bg);color:var(--ink);border-radius:10px;padding:10px 15px;flex:1;max-width:440px}.study-layout{display:grid;grid-template-columns:218px minmax(0,1fr);gap:30px;align-items:start;padding-top:4px}.topic-side{position:sticky;top:96px;padding:12px 0 25px}.unit-back{display:block;font-size:12px;color:var(--muted);font-weight:650;margin:0 0 30px;padding-left:10px}.topic-side>.eyebrow{padding-left:10px;font-size:10px}.topic-side nav{display:grid;gap:5px}.topic-side nav a{display:flex;align-items:center;gap:10px;padding:12px 11px;font-size:12px;font-weight:600;border-radius:10px;color:var(--muted)}.topic-side nav a .icon{width:16px;height:16px}.topic-side nav a[aria-current],.topic-side nav a:hover{background:#e7effe;color:#1d5bc4}.topic-side nav a[aria-current]{font-weight:750}.sidebar-note{padding:22px 11px;font-size:11px;line-height:1.7;color:var(--muted)}.study-main{min-width:0}.topic-heading{border-radius:20px;background:linear-gradient(105deg,#edf5ff 65%,#edf5ff88),url('/assets/alpine-sunrise.webp') right 40%/cover;padding:29px 30px}.topic-heading h1{font-size:39px;letter-spacing:-.045em;max-width:760px}.topic-heading>p{font-size:16px;max-width:650px;color:#465f80;margin:14px 0 22px}.learning-goal{display:flex;gap:10px;align-items:start;background:#ffffffb3;border:1px solid #ffffff;border-radius:12px;padding:13px 16px}.learning-goal>span{color:#16866c;padding-top:2px}.learning-goal .icon{width:18px}.learning-goal p{margin:0;font-size:12px;color:#4d6380;line-height:1.5}.learning-goal strong{display:block;color:#18385e;font-size:11px;text-transform:uppercase;letter-spacing:.07em;margin-bottom:3px}.topic-actions{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;position:sticky;top:75px;z-index:10;padding:12px 0;background:var(--bg)}.topic-actions a{border:1px solid var(--line);background:var(--paper);border-radius:10px;padding:13px 10px;display:flex;justify-content:center;align-items:center;gap:8px;font-size:12px;font-weight:650}.topic-actions a:hover{color:var(--blue);border-color:#93b8f7}.topic-actions .icon{width:17px;height:17px}.topic-section{background:var(--paper);border:1px solid var(--line);border-radius:18px;padding:28px;margin:11px 0 24px}.topic-section h2{font-size:25px;margin-bottom:19px}.idea-list{display:grid;gap:22px}.idea{display:flex;gap:15px}.idea>span{font-size:11px;color:#7b96b8;padding-top:3px;font-weight:750}.idea h3{font-size:18px;line-height:1.35;letter-spacing:-.025em;margin-bottom:8px}.idea p{font-size:14px;line-height:1.8;color:var(--muted);margin:0;max-width:740px}.vocab{background:#f7faff;padding:15px 18px;margin-top:25px}.vocab summary{font-size:13px}.vocab dl{margin-bottom:0;display:grid;gap:14px}.vocab dt{font-size:13px;font-weight:750;margin-bottom:4px}.vocab dd{margin:0;font-size:13px;color:var(--muted);line-height:1.6}.concept-diagram{padding:14px 22px;border-radius:13px;background:#edf5ff;margin-bottom:26px}.concept-diagram>.wide-numberline{max-width:590px;margin:auto}.example-section>p{font-size:13px;color:var(--muted)}.worked-grid{display:grid;gap:15px}.worked-card{background:#f5f2fe;border:1px solid #eae3fb;border-radius:13px;padding:22px}.worked-card>h3{font-size:22px;letter-spacing:-.02em;margin:7px 0 17px}.worked-steps{padding-left:22px;margin:0;display:grid;gap:12px;counter-reset:step}.worked-steps li{padding-left:7px;font-size:14px;line-height:1.7;color:#4f5276}.worked-actions{display:flex;align-items:center;gap:15px;margin-top:19px}.worked-actions .secondary{font-size:12px;padding:9px 13px}.text-button{border:0;color:var(--blue);background:transparent;font-weight:650;font-size:12px;padding:10px 0;min-height:44px}.text-button:hover{text-decoration:underline}.misconception{background:#fff6e8;border:1px solid #f0e2c9;padding:24px 27px;border-radius:17px;margin-bottom:24px;color:#694f28}.misconception .section-kicker{color:#8c6e3e}.misconception h2{font-size:21px;line-height:1.4}.misconception details{background:#fffaf1;border-color:#eedfc7;margin-top:18px}.misconception summary{font-size:13px}.misconception p{font-size:14px;line-height:1.7}.guided-section{padding:28px;border-radius:18px;background:#eaf6f2;border:1px solid #d9ebe5;margin:24px 0}.guided-section h2{font-size:25px}.guided-problem{font-size:19px;line-height:1.5;font-weight:650;margin:20px 0}.guided-step{border-radius:12px;background:var(--paper);padding:20px;margin-top:13px;border:1px solid #e0ebe8}.guided-step[aria-disabled=true]{opacity:.6}.guided-step>label{display:block;font-size:14px;font-weight:600;margin-bottom:13px;line-height:1.6}.guided-step>label>span{display:block;color:#178269;font-size:10px;font-weight:750;text-transform:uppercase;letter-spacing:.08em;margin-bottom:6px}.guided-step>div{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.guided-step input{width:110px;border:1px solid #b6c9c3;border-radius:9px;padding:11px;background:var(--paper);color:var(--ink)}.guided-step .primary{font-size:12px}.guided-feedback{font-size:13px!important;margin:12px 0 0!important;line-height:1.7}.correct{color:#087b50}.incorrect{color:#ad4435}.guided-step.complete{border-color:#97cdbb}.counter-model{background:#edf5ff;border:1px solid #dce9fa;border-radius:17px;padding:27px;margin:24px 0}.counter-model h2{font-size:24px}.counter-model>p{font-size:14px;line-height:1.7;color:#4b6688}.counter-controls{display:flex;gap:13px;align-items:end;flex-wrap:wrap;margin:20px 0}.counter-controls label{font-size:12px;display:grid;gap:6px;color:#465f80}.counter-controls select{padding:10px 16px;border-radius:9px;border:1px solid #bfcee3;min-width:100px;min-height:44px;background:var(--paper);color:var(--ink)}.counter-controls button{font-size:12px}.counter-tray{border:1px solid #d6e4f6;display:grid;gap:12px;background:#ffffff88;padding:19px;border-radius:13px;min-height:125px}.counter-group{display:flex;flex-wrap:wrap;gap:10px;min-height:34px}.counter{height:34px;width:34px;border-radius:50%;display:grid;place-items:center;font:700 23px Arial;box-shadow:inset 0 -3px 0 #00000012}.counter.positive{background:#1667d8;color:white}.counter.negative{background:#d47b3c;color:white}.counter.cancelled{background:#dfe6ec;color:#536b81;box-shadow:none;text-decoration:line-through;text-decoration-thickness:2px}.practice-v2{padding:28px;border-radius:18px;background:#edf3ff;border:1px solid #dce6fa;margin:24px 0}.practice-v2 h2{font-size:25px}.practice-v2>p{font-size:14px;color:var(--muted)}.practice-settings{display:flex;align-items:end;gap:12px;flex-wrap:wrap;margin:23px 0 20px}.practice-settings label{display:grid;gap:6px;font-size:11px;font-weight:650;color:var(--muted)}.practice-settings select{padding:11px 12px;border:1px solid #bfcee5;border-radius:9px;min-height:44px;background:var(--paper);color:var(--ink);font-size:12px}.practice-settings button{font-size:12px}.v2-workspace{padding:24px;background:var(--paper);border:1px solid var(--line);border-radius:14px}.v2-progress{background:#e5ecf9;height:5px;border-radius:7px;margin:12px 0 25px;overflow:hidden}.v2-progress span{display:block;background:var(--blue);width:0;height:100%;transition:width .2s}.v2-equation{font-size:30px;line-height:1.45;letter-spacing:-.025em;margin:21px 0}.v2-context{background:var(--soft);font-size:15px;line-height:1.75;padding:17px 19px;border-radius:11px}.v2-workspace form{display:flex;align-items:end;gap:10px;flex-wrap:wrap}.v2-workspace form label{display:grid;gap:6px;font-size:11px;font-weight:650}.v2-workspace input{padding:11px 14px;border:1px solid #b5c7e0;border-radius:9px;width:130px;min-height:44px;background:var(--paper);color:var(--ink);font-size:17px}.v2-workspace form button{font-size:12px}.practice-bottom{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-top:12px}.practice-bottom .primary{font-size:12px}.practice-footnote{display:flex;flex-wrap:wrap;gap:5px 20px;font-size:11px;color:var(--muted);line-height:1.7;margin:17px 0 5px}.local-history{font-size:11px;color:var(--muted);margin-top:10px}#v2-feedback{font-size:14px;line-height:1.7;margin-top:16px;min-height:24px}#v2-hints{font-size:13px;line-height:1.8;padding:14px 17px;background:#fff6e7;border-radius:10px;color:#785724;margin:12px 0}#v2-explanation{font-size:13px;line-height:1.8;padding:16px 19px;border-radius:11px;background:var(--soft);margin:15px 0}#v2-explanation ol{padding-left:20px;margin-bottom:0}#v2-summary{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:24px}#v2-summary>div{background:var(--soft);border-radius:11px;padding:16px;text-align:center}#v2-summary strong{display:block;font-size:29px;color:var(--blue)}#v2-summary span{font-size:11px;color:var(--muted)}#v2-summary p{grid-column:1/-1;font-size:14px;line-height:1.7}.context-callout{background:#edf7f4;padding:19px 21px;border-radius:12px;margin-bottom:18px}.context-callout strong{font-size:12px;color:#157d65}.context-callout p{font-size:14px;color:var(--muted);line-height:1.8;margin:8px 0 0}.topic-section .resource-grid{grid-template-columns:1fr 1fr}.text-link{font-size:12px;display:inline-block;margin-top:16px}.mobile-topic-picker{display:none}.related-section .related-links{grid-template-columns:1fr 1fr}.dark .unit-hero,.dark .topic-heading{background:linear-gradient(105deg,#192e48 55%,#192e48ae),url('/assets/alpine-sunrise.webp') center/cover;border-color:#304866}.dark .unit-hero p,.dark .topic-heading>p{color:#bed0e5}.dark .hero-math>span,.dark .hero-math>strong,.dark .learning-goal{background:#223b56;border-color:#33516e;color:#c2d9ff}.dark .learning-goal p,.dark .learning-goal strong{color:#d2e3f7}.dark .rule-check{background:#242e4d;border-color:#344263}.dark .topic-card,.dark .topic-card-grid{border-color:var(--line)}.dark .topic-side nav a[aria-current]{background:#213b60;color:#aaccff}.dark .concept-diagram,.dark .counter-model,.dark .practice-v2{background:#192f4b;border-color:#30496b}.dark .vocab,.dark .worked-card{background:#242d48;border-color:#3a4162}.dark .worked-steps li{color:#c9d2e9}.dark .guided-section,.dark .context-callout{background:#193b36;border-color:#30594c}.dark .context-callout strong{color:#8ddac7}.dark .misconception{background:#3d321f;border-color:#66512c;color:#eed5b2}.dark .misconception .section-kicker{color:#e0be8a}.dark .misconception details{background:#443824;border-color:#6c5836}.dark .counter-tray{background:#14283f;border-color:#34526f}.dark .counter-model>p,.dark .counter-controls label{color:#bfd0e5}.dark .section-kicker{color:#a6bfdf}.dark #v2-hints{background:#423823;color:#f4dba6}.dark .correct{color:#82dfb7}.dark .incorrect{color:#ffb5a7}.dark .unit-help a,.dark .text-link,.dark .text-button,.dark .topic-link{color:#9dc7ff}.dark .guided-step>label>span{color:#8ddac7}
@media(max-width:1050px){.study-layout{grid-template-columns:190px minmax(0,1fr);gap:20px}.topic-side nav a{font-size:11px}.topic-heading h1{font-size:33px}.topic-heading{padding:25px}.topic-section,.guided-section,.practice-v2,.counter-model{padding:24px}.topic-actions a{font-size:11px;gap:6px}.topic-card-grid{gap:13px}.topic-card{padding:20px}.topic-card h3{font-size:18px}.rule-check{grid-template-columns:1fr}.rule-check h2{max-width:none}.unit-hero{grid-template-columns:1fr 170px}.hero-math{gap:8px}.hero-math>span,.hero-math>strong{width:47px;height:62px;font-size:32px}}
@media(max-width:800px){.study-layout{grid-template-columns:1fr;gap:0}.topic-side{display:none}.mobile-topic-picker{display:flex;align-items:center;justify-content:space-between;gap:15px;padding:9px 0 17px;font-size:11px;font-weight:650;color:var(--muted)}.mobile-topic-picker select{background:var(--paper);color:var(--ink);border:1px solid var(--line);border-radius:9px;padding:11px 13px;font-size:12px;max-width:70%;min-height:44px}.topic-heading h1{font-size:35px}.topic-card-grid{grid-template-columns:1fr 1fr}.unit-hero{padding:28px}.unit-hero h1{font-size:48px}.unit-hero p{font-size:15px}.unit-hero .unit-buttons{flex-wrap:wrap}.topic-actions{top:65px}.topic-section{margin-top:10px}}
@media(max-width:540px){.unit-hero{grid-template-columns:1fr;padding:24px;gap:0;border-radius:17px}.hero-math{display:none}.unit-hero h1{font-size:45px}.unit-hero p{font-size:14px;line-height:1.7}.unit-buttons{gap:9px}.unit-buttons a{font-size:12px;padding:10px 13px}.topic-directory .section-top{align-items:end}.topic-directory .section-top>span{font-size:10px;white-space:nowrap}.topic-directory .section-top h2{font-size:22px}.topic-card-grid{grid-template-columns:1fr}.topic-card{padding:19px;display:grid;grid-template-columns:90px 1fr;gap:0 17px}.topic-mark{grid-column:1;grid-row:1/4;min-width:0;width:90px;align-self:start;margin:1px 0 0;font-size:14px;padding:10px 6px}.topic-card h3{font-size:18px;grid-column:2}.topic-card p{grid-column:2;margin:8px 0 11px;font-size:12px;line-height:1.6}.topic-link{grid-column:2;font-size:11px}.topic-progress{grid-column:2}.rule-check{padding:21px;gap:13px}.rule-check h2{font-size:22px}.rule-comparison{gap:10px}.rule-comparison>div{padding:15px 12px}.rule-comparison strong{font-size:15px;letter-spacing:-.03em}.rule-comparison a{font-size:11px}.resource-accordion{padding:18px}.resource-accordion summary{font-size:16px;line-height:1.5}.resource-accordion summary span{float:none;display:block;font-size:11px;margin:8px 0 0 15px}.resource-search-label{display:grid;gap:8px}.resource-search-label input{width:100%;min-width:0}.topic-heading{padding:23px 21px}.topic-heading h1{font-size:31px;line-height:1.15}.topic-heading>p{font-size:14px;line-height:1.7}.learning-goal{padding:12px;gap:8px}.learning-goal p{font-size:12px}.topic-actions{gap:5px;padding:10px 0;top:65px}.topic-actions a{padding:11px 5px;font-size:10px;gap:5px}.topic-actions .icon{width:14px;height:14px}.topic-section,.guided-section,.practice-v2,.counter-model{padding:22px 19px;border-radius:15px}.topic-section h2,.guided-section h2,.practice-v2 h2,.counter-model h2{font-size:22px}.idea{gap:12px}.idea h3{font-size:17px}.idea p{font-size:14px;line-height:1.85}.idea-list{gap:24px}.concept-diagram{padding:17px 12px}.concept-diagram .mobile-numberline .numberline text{font-size:17px}.worked-card{padding:20px 17px}.worked-card>h3{font-size:20px;line-height:1.5}.worked-steps{padding-left:17px}.worked-steps li{font-size:13px}.worked-actions{gap:15px}.misconception{padding:22px 20px}.misconception h2{font-size:19px}.guided-problem{font-size:17px}.guided-step{padding:17px 14px}.guided-step input{width:90px}.guided-step .primary{padding:10px 12px}.counter-controls{gap:10px}.counter-controls label{font-size:11px}.counter-controls select{min-width:104px}.counter-tray{padding:14px}.counter{width:29px;height:29px;font-size:20px}.counter-group{gap:7px}.practice-settings{display:grid;grid-template-columns:1fr 1fr;gap:12px}.practice-settings label{min-width:0}.practice-settings select{min-width:0;width:100%;font-size:11px;padding:10px 7px}.practice-settings button{justify-self:start}.v2-workspace{padding:19px 16px}.v2-equation{font-size:26px}.v2-workspace form{gap:9px}.v2-workspace input{width:96px;font-size:16px}.v2-workspace form button{font-size:11px;padding:11px 12px}.practice-top{font-size:11px}.v2-context{font-size:14px;padding:15px}.practice-bottom{flex-wrap:wrap;gap:8px}.practice-bottom .text-button{font-size:11px}.topic-section .resource-grid{grid-template-columns:1fr}#v2-summary{gap:8px}#v2-summary>div{padding:13px 7px}#v2-summary span{font-size:10px}.unit-help{padding:22px}.unit-help h2{font-size:21px}.resource-grid{grid-template-columns:1fr}.learning-goal .icon{width:16px}}
@media(max-width:350px){.topic-card{grid-template-columns:70px 1fr;gap:0 12px}.topic-mark{width:70px;font-size:12px}.topic-actions .icon{display:none}.topic-actions a{min-height:42px}.practice-settings{grid-template-columns:1fr}.unit-hero{padding:20px}.unit-buttons{flex-direction:column;align-items:start}.guided-step>div{gap:7px}.guided-step .primary{font-size:11px}.v2-equation{font-size:23px}.rule-comparison{grid-template-columns:1fr}.topic-heading h1{font-size:28px}}
@media print{.topic-side,.topic-actions,.mobile-topic-picker,.practice-v2,.worked-actions,.guided-section{display:none!important}.study-layout{display:block}.topic-heading{background:none;padding:0}.worked-steps li[hidden]{display:list-item!important}.topic-section,.worked-card{break-inside:avoid}.study-main{width:100%}}
/* Author workspace */
.editor-heading{display:flex;justify-content:space-between;align-items:end;gap:30px;padding:16px 0 25px}.editor-heading h1{font-size:36px;letter-spacing:-.045em}.editor-heading p{font-size:14px;color:var(--muted);margin-bottom:0}.draft-state{display:grid;justify-items:end;gap:12px}.draft-state>span{font-size:11px;color:#287e68}.draft-state .secondary{font-size:11px;padding:9px 13px}.author-toolbar{display:flex;gap:20px;align-items:end;padding:18px 20px;border:1px solid var(--line);border-radius:13px;background:var(--paper);margin-bottom:20px;position:sticky;top:76px;z-index:11;box-shadow:0 3px 15px #163b6108}.author-toolbar>label,.preview-width label,.publish-options label{display:grid;gap:6px;font-size:11px;font-weight:650;color:var(--muted)}.author-toolbar select,.publish-options select{padding:10px 12px;font-size:12px;border:1px solid #c5d3e6;border-radius:8px;min-height:43px;background:var(--paper);color:var(--ink)}.author-toolbar>label{min-width:200px}.author-toolbar>.primary{margin-left:auto;font-size:12px}.author-workspace{display:grid;grid-template-columns:340px minmax(0,1fr);gap:22px;align-items:start}.author-fields{padding:24px;background:var(--paper);border:1px solid var(--line);border-radius:15px;max-height:850px;overflow-y:auto}.author-fields>h2{font-size:21px}.author-fields>p{font-size:12px;line-height:1.6}.author-field{display:grid;gap:8px;margin:19px 0;font-size:12px;font-weight:650}.author-field input,.author-field textarea,.author-field select{width:100%;min-width:0;border:1px solid #bccde3;border-radius:8px;padding:11px 12px;color:var(--ink);background:var(--paper);font-size:13px;font-weight:450;line-height:1.7}.author-field textarea{min-height:125px;resize:vertical}.author-field small{font-size:10px;font-weight:400;line-height:1.6;color:var(--muted)}.author-tip{padding:14px 16px;background:var(--soft);border-radius:10px;font-size:12px;color:var(--muted);line-height:1.7}.author-resource{padding:14px;margin:11px 0}.author-resource summary{font-size:12px;line-height:1.65;font-weight:650}.author-preview{min-width:0;position:sticky;top:165px;border-radius:14px;border:1px solid #d5e0ef;background:#e5edf7;overflow:hidden}.preview-label{display:flex;gap:15px;justify-content:space-between;padding:12px 17px;font-size:10px;color:#55708f;background:#edf3fb}.preview-label span:first-child{font-weight:700}.preview-frame-wrap{overflow:auto;padding:0;display:flex;justify-content:center;max-width:100%;background:#dce6f4}.author-preview iframe{border:0;display:block;width:100%;max-width:100%;height:780px;background:white}.publishing-panel{padding:30px;border:1px solid var(--line);border-radius:17px;background:var(--paper);margin-top:30px;scroll-margin-top:170px}.publishing-panel h2{font-size:27px}.publishing-panel>p{font-size:14px;color:var(--muted);line-height:1.8;max-width:850px}.publish-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;padding:0;list-style:none;margin:25px 0}.publish-steps li{padding:19px;border-radius:12px;background:var(--soft)}.publish-steps strong{display:block;font-size:15px;margin-bottom:8px}.publish-steps span{display:block;font-size:12px;color:var(--muted);line-height:1.7}.publish-options{display:flex;gap:18px;flex-wrap:wrap;align-items:end;margin:25px 0 18px}.publish-options select{max-width:100%}.checkline{font-size:12px;display:flex;align-items:center;gap:10px;color:var(--muted);line-height:1.6}.checkline input{width:18px;height:18px;flex-shrink:0}.import-button{font-size:12px;cursor:pointer}.publishing-panel .small-print{font-size:11px}.publishing-panel .editor-actions .secondary,.publishing-panel .editor-actions .primary{font-size:12px}.dark .author-preview{border-color:#3c526e;background:#1a2b43}.dark .preview-label{background:#213650;color:#c1d2e5}.dark .preview-frame-wrap{background:#162840}.dark .draft-state>span{color:#98dcc7}
@media(max-width:1050px){.author-workspace{grid-template-columns:300px minmax(0,1fr)}.author-fields{padding:21px}.author-toolbar{gap:15px}.author-toolbar>label{min-width:180px}.preview-label span:last-child{display:none}}
@media(max-width:800px){.editor-heading{align-items:start;flex-direction:column;gap:17px}.draft-state{display:flex;gap:18px;align-items:center;flex-wrap:wrap}.editor-heading h1{font-size:32px}.author-workspace{grid-template-columns:1fr}.author-fields{max-height:none}.author-preview{position:static}.author-toolbar{top:66px;flex-wrap:wrap;padding:15px;gap:12px}.author-toolbar>label{min-width:0;flex:1}.author-toolbar .preview-width{display:none}.author-toolbar>.primary{margin-left:0}.author-preview iframe{height:700px}.publish-steps{grid-template-columns:1fr;gap:10px}.publishing-panel{padding:23px}.publish-options{display:grid;grid-template-columns:1fr}.publish-options label{min-width:0}.publish-options select{width:100%}}
@media(max-width:430px){.editor-heading h1{font-size:29px}.author-toolbar{gap:10px}.author-toolbar>label{flex-basis:100%}.author-toolbar select{width:100%}.author-toolbar>.primary{width:100%}.author-fields{padding:20px}.author-field textarea{min-height:120px}.author-preview iframe{height:640px}.publishing-panel{padding:21px}.publishing-panel h2{font-size:23px}.editor-actions{align-items:start;flex-direction:column}.publishing-panel .checkline{align-items:start}.draft-state>span{font-size:11px}}
.number-sense-model,.pattern-model,.division-model{padding:27px;background:#edf5ff;border:1px solid #dce9fa;border-radius:17px;margin:24px 0}.number-sense-model h2,.pattern-model h2,.division-model h2{font-size:24px}.number-sense-model>p,.pattern-model>p,.division-model>p{font-size:14px;color:var(--muted);line-height:1.8}.range-label{display:grid;gap:12px;margin:22px 0;font-size:12px;font-weight:600;color:var(--muted)}.range-label input{width:100%;accent-color:#1464ed;min-height:30px;cursor:pointer}.sense-line{position:relative;margin:52px 15px 20px;height:65px}.sense-axis{height:3px;position:absolute;top:20px;left:0;right:0;background:#7b96b8}.sense-tick{position:absolute;top:32px;font-size:12px;color:var(--muted)}.sense-tick:before{content:'';height:11px;position:absolute;left:50%;top:-16px;border-left:2px solid #7b96b8}.sense-tick.start{left:0;transform:translateX(-50%)}.sense-tick.middle{left:50%;transform:translateX(-50%)}.sense-tick.end{right:0;transform:translateX(50%)}.sense-point{position:absolute;left:30%;top:15px;width:13px;height:13px;border-radius:50%;background:#1464ed;transform:translateX(-50%)}.sense-point b{position:absolute;bottom:24px;left:50%;transform:translateX(-50%);font-size:16px;background:#1464ed;color:white;padding:4px 10px;border-radius:9px;white-space:nowrap}.sense-facts{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.sense-facts>div{padding:16px 10px;border-radius:11px;background:var(--paper);text-align:center}.sense-facts span{font-size:11px;color:var(--muted)}.sense-facts strong{display:block;font-size:25px;margin-top:7px}.pattern-equation{background:var(--paper);padding:22px;border:1px solid var(--line);border-radius:12px;font:700 30px Manrope,sans-serif;text-align:center;margin:20px 0}.pattern-table-wrap{border-radius:12px;overflow:hidden;border:1px solid #d3e1f2;background:var(--paper)}.pattern-table{width:100%;border-collapse:collapse;text-align:center;font-size:13px}.pattern-table caption{font-size:11px;text-align:left;background:#dfeafa;padding:12px 15px;color:#486488}.pattern-table th,.pattern-table td{padding:10px 12px;border-bottom:1px solid var(--line)}.pattern-table thead th{font-size:11px;color:var(--muted)}.pattern-table tr.selected{background:#dfedff;color:#155dc3;font-weight:750}.dark .number-sense-model,.dark .pattern-model,.dark .division-model{background:#192f4b;border-color:#30496b}.dark .pattern-table caption{background:#27415f;color:#c6d9f1}.dark .pattern-table tr.selected{background:#294f7c;color:#cbe4ff}
@media(max-width:540px){.number-sense-model,.pattern-model,.division-model{padding:22px 19px}.number-sense-model h2,.pattern-model h2,.division-model h2{font-size:22px}.sense-facts{gap:8px}.sense-facts>div{padding:14px 6px}.sense-facts span{font-size:10px}.sense-facts strong{font-size:24px}.pattern-equation{font-size:24px;padding:18px 10px}.pattern-table{font-size:12px}.pattern-table th,.pattern-table td{padding:9px 6px}}
.practice-page .practice-v2>.section-kicker,.practice-page .practice-v2>h2,.practice-page .practice-v2>p{display:none}.practice-page .topic-heading>p{margin-bottom:0}.practice-page .practice-settings{margin-top:0}@media(max-width:540px){.unit-hero{padding:23px 21px}.unit-hero>.eyebrow,.unit-hero>div>.eyebrow{display:none}.unit-hero .breadcrumb{margin-bottom:12px}.unit-hero h1{font-size:40px;margin:6px 0 10px}.unit-hero p{font-size:13px;line-height:1.7;margin:9px 0 17px}.unit-buttons{margin-top:17px;gap:8px;flex-direction:row;align-items:center}.unit-buttons a{font-size:11px;padding:10px 11px;gap:6px}.unit-buttons .icon{width:16px;height:16px}.topic-card-grid{grid-template-columns:1fr 1fr;gap:12px}.topic-card{display:flex;position:relative;min-height:130px;padding:17px 15px}.topic-mark{width:auto;min-width:64px;font-size:12px;padding:7px 9px;margin:0 0 13px;align-self:flex-start}.topic-card h3{font-size:16px;line-height:1.35;padding-right:0}.topic-card p{display:none}.topic-link{position:absolute;top:21px;right:13px;font-size:0;gap:0}.topic-link .icon{width:15px;height:15px}.topic-progress{font-size:9px;line-height:1.5;margin-top:10px}.topic-directory .section-top>span{display:none}.practice-page .topic-heading{padding:20px 21px}.practice-page .topic-heading .eyebrow{display:none}.practice-page .topic-heading h1{font-size:29px}.practice-page .topic-heading>p{font-size:13px;line-height:1.7;margin-top:11px}.practice-page .breadcrumb{margin-bottom:12px}.practice-page .practice-v2{margin-top:17px}.practice-page .practice-settings{grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:10px}.practice-page .practice-settings select{font-size:10px;padding:10px 6px}.practice-page .v2-progress{margin-bottom:15px}.practice-page .v2-equation{margin:16px 0}.practice-page .v2-workspace{padding:18px 14px}}
@media(max-width:350px){.topic-card{padding:16px 12px;min-height:125px}.topic-card h3{font-size:15px}.unit-hero h1{font-size:37px}.unit-buttons a{font-size:10px;padding:10px;gap:4px}.unit-buttons .icon{width:14px;height:14px}}

@media(min-width:761px) and (max-width:800px){.topic-actions{top:76px}.author-toolbar{top:76px}}
/* Instruction-first unit composition, approved reference family. */
.reference-unit{display:grid;grid-template-columns:185px minmax(0,1fr);gap:22px}.subject-rail{padding:10px 0}.subject-rail .eyebrow{margin:28px 0 16px}.subject-rail nav{display:grid;gap:7px}.subject-rail nav a{display:flex;align-items:center;gap:12px;padding:10px;border-radius:12px;font-size:12px;min-height:52px}.subject-rail nav a[aria-current]{background:#dfecff;color:#0755d6;font-weight:700}.unit-symbol{display:grid;place-items:center;width:35px;height:38px;border-radius:9px;background:#1464ed;color:white;font-size:19px;flex-shrink:0}.subject-rail nav a:nth-child(2n) .unit-symbol{background:#b7356d}.subject-rail nav a:nth-child(3n) .unit-symbol{background:#008377}.rail-photo{position:relative;margin:30px 0 0;border-radius:15px;overflow:hidden;height:350px}.rail-photo img{width:100%;height:100%;object-fit:cover}.rail-photo:after{content:'';position:absolute;inset:40% 0 0;background:linear-gradient(transparent,#052633)}.rail-photo figcaption{position:absolute;z-index:1;bottom:22px;left:18px;right:15px;color:white;font-size:18px;line-height:1.5}.reference-unit-main{min-width:0}.immersive-heading{border-radius:19px;min-height:240px;padding:30px 32px 55px;color:white;background:linear-gradient(90deg,#061c31dc,#08253b20),url('/assets/alpine-sunrise.webp') center 48%/cover}.immersive-heading .breadcrumb{color:#fff}.immersive-heading h1{font-size:49px}.immersive-heading p{max-width:660px;font-size:16px;line-height:1.65;margin-bottom:0}.reference-columns{display:grid;grid-template-columns:minmax(0,1fr) 225px;gap:16px;margin: -25px 14px 0;position:relative}.reference-content{background:var(--paper);border:1px solid var(--line);border-radius:15px;padding:0 13px 18px;min-width:0}.learning-tabs{display:grid;grid-template-columns:repeat(6,1fr);gap:4px;border-bottom:1px solid var(--line);padding:9px 0;margin-bottom:13px}.learning-tabs a{display:flex;align-items:center;justify-content:center;gap:5px;font-size:10px;font-weight:700;min-height:43px;border-radius:7px}.learning-tabs a:nth-child(3n+1){color:#0757db}.learning-tabs a:nth-child(3n+2){color:#7141c4}.learning-tabs a:nth-child(3n){color:#007b5b}.learning-tabs .icon{width:17px;height:17px}.reference-block{padding:20px;border-radius:13px;margin:12px 0}.blue-block{background:linear-gradient(125deg,#eaf4ff,#f4f9ff)}.purple-block{background:linear-gradient(120deg,#f1ecff,#f7f5ff)}.numbered-heading{display:flex;gap:13px;align-items:start}.numbered-heading>b{display:grid;place-items:center;background:#1464ed;color:#fff;width:34px;height:37px;border-radius:9px;flex-shrink:0;font-size:21px}.purple-block .numbered-heading>b{background:#7945df}.numbered-heading h2{font-size:21px}.numbered-heading p{font-size:13px;margin:7px 0 14px;line-height:1.6}.reference-learn{display:grid;grid-template-columns:minmax(0,1fr) 190px;gap:15px;align-items:center}.reference-key{background:#ffffffa8;padding:15px;border-radius:12px;font-size:12px}.reference-key h3{font-size:16px}.reference-key ul{padding-left:17px;line-height:1.7}.reference-key li{margin-bottom:8px}.reference-key a{color:#0757db;font-size:11px;font-weight:700}.quiet-caption{font-size:11px;color:var(--muted);text-align:center}.reference-example{display:grid;grid-template-columns:minmax(0,1fr) 180px;gap:14px}.reference-example>div,.quick-try{padding:15px;background:#ffffffb0;border-radius:11px;min-width:0}.line-presets{display:flex;flex-wrap:wrap;gap:5px;margin-bottom:15px}.line-presets button{background:var(--paper);border:1px solid var(--line);padding:8px;border-radius:7px;font-size:11px;color:var(--ink)}.line-presets button[aria-pressed=true]{color:#0757db;border-color:#1464ed}.reference-example h3{font-size:21px}.reference-example svg{width:100%;height:auto;color:#233c5e}.reference-example svg text{font-size:14px}.journey-hop{stroke:#a84d0e;stroke-width:2;fill:none}.line-reason{font-size:12px;line-height:1.7}.reference-example .secondary{font-size:11px}.quick-try{display:flex;flex-direction:column;align-items:start;gap:10px}.quick-try label{font-size:11px}.quick-try input{width:100%;min-height:44px;border:1px solid #b7c9e2;border-radius:8px;padding:10px;background:var(--paper);color:var(--ink)}.quick-try p,.quick-try a{font-size:12px;line-height:1.7}.quick-try h3{margin:12px 0}.your-model{margin-top:15px;font-size:12px}.your-model summary{font-weight:700;cursor:pointer;min-height:44px;padding:10px 0}.journey-controls{display:flex;flex-wrap:wrap;gap:12px}.journey-controls label{display:grid;gap:5px}.journey-controls input,.journey-controls select{width:110px;min-height:44px;border:1px solid #b8c9e0;padding:8px;border-radius:8px;background:var(--paper);color:var(--ink)}.compact-paths{margin-top:25px}.compact-paths nav{display:grid;grid-template-columns:1fr 1fr;gap:0 18px}.compact-paths nav>a{display:flex;gap:12px;align-items:center;padding:16px 0;border-bottom:1px solid var(--line)}.compact-paths nav b,.unit-companion nav b{background:#e7efff;color:#0757db;border-radius:50%;min-width:26px;height:26px;display:grid;place-items:center;font-size:12px}.compact-paths strong{font-size:13px;display:block}.compact-paths small{display:block;font-size:11px;line-height:1.6;margin-top:5px}.compact-paths .icon{margin-left:auto;width:16px}.compact-paths h2,.world-connections h2{font-size:20px}.compact-paths .section-top>a{font-size:11px}.world-connections{margin-top:28px}.world-connections>div:last-child{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.world-connections img{width:100%;height:100px;object-fit:cover;border-radius:10px}.world-connections h3{font-size:13px;margin-top:10px}.world-connections p{font-size:11px;color:var(--muted)}.unit-companion>section{background:var(--paper);border:1px solid var(--line);border-radius:13px;padding:17px;margin-bottom:15px}.unit-companion h2{font-size:18px}.unit-companion section>p{font-size:11px;color:var(--muted)}.unit-companion nav{display:grid;gap:4px}.unit-companion nav a{display:flex;gap:10px;align-items:center;min-height:42px;font-size:11px}.quick-tool{display:flex;gap:10px;align-items:center;font-size:12px;min-height:46px}.quick-tool>span{background:#e7efff;color:#0757db;padding:6px;border-radius:7px;display:flex}.companion-photo{display:block;background:var(--paper);border:1px solid var(--line);border-radius:13px;padding:10px}.companion-photo img{width:100%;height:130px;object-fit:cover;border-radius:8px}.companion-photo h3{font-size:15px;margin:12px 5px 8px}.companion-photo p,.companion-photo>span{font-size:12px;margin:8px 5px;display:block}.companion-photo>span{color:#0757db}.reference-unit .resource-grid{grid-template-columns:1fr 1fr}.reference-unit .resource-section h2{font-size:20px}.reference-unit .resource{font-size:12px}.reference-unit .unit-help{padding:20px}.reference-unit .unit-help h2{font-size:20px}.reference-unit .unit-help p{font-size:13px}.dark .reference-block,.dark .reference-key,.dark .reference-example>div,.dark .quick-try{background:#1d304b}.dark .subject-rail nav a[aria-current]{background:#213b60;color:#bdd7ff}.dark .reference-key a,.dark .companion-photo>span{color:#b5d5ff}
@media(min-width:1450px){.shell:has(.reference-unit){max-width:1600px}.reference-unit{grid-template-columns:220px minmax(0,1fr)}.reference-columns{grid-template-columns:minmax(0,1fr) 250px}.learning-tabs a{font-size:12px}}
@media(max-width:1150px){.reference-unit{grid-template-columns:155px minmax(0,1fr);gap:15px}.reference-columns{grid-template-columns:minmax(0,1fr);margin-left:10px;margin-right:10px}.unit-companion{display:none}.reference-learn{grid-template-columns:minmax(0,1fr) 180px}.subject-rail nav a{font-size:11px;padding:7px}.rail-photo{height:300px}}
@media(max-width:760px){.reference-unit{display:block}.subject-rail{display:none}.immersive-heading{padding:24px 23px 44px;min-height:215px}.immersive-heading h1{font-size:38px}.immersive-heading p{font-size:14px}.reference-columns{margin:-20px 0 0}.reference-content{padding:0 12px 15px}.learning-tabs{grid-template-columns:repeat(3,1fr);gap:3px}.learning-tabs a{font-size:11px;min-height:44px}.reference-block{padding:17px 14px}.numbered-heading h2{font-size:20px}.numbered-heading>b{width:29px;height:32px;font-size:18px}.reference-learn{grid-template-columns:1fr}.reference-key{font-size:12px}.reference-key ul{display:grid;grid-template-columns:1fr 1fr;gap:5px 20px}.reference-example{grid-template-columns:1fr}.quick-try{display:grid;grid-template-columns:1fr 90px;gap:10px}.quick-try .eyebrow,.quick-try h3,.quick-try p,.quick-try>a{grid-column:1/-1}.quick-try h3{margin:0}.quick-try label{grid-column:1/-1}.quick-try input{min-width:0}.compact-paths nav{grid-template-columns:1fr}.world-connections>div:last-child{grid-template-columns:1fr}.world-connections>div>a{display:grid;grid-template-columns:90px 1fr;gap:0 12px}.world-connections img{grid-row:1/3;height:80px}.world-connections h3{align-self:end}.world-connections p{margin-top:5px}.reference-unit .resource-grid{grid-template-columns:1fr}.reference-unit .mobile-numberline{display:block}.reference-unit .wide-numberline{display:none}}
@media(min-width:761px) and (max-width:1000px){.reference-unit{display:block}.subject-rail{display:none}.reference-learn{grid-template-columns:minmax(0,1fr) 200px}.reference-columns{margin-left:0;margin-right:0}}
.reference-unit .reference-learn .numberline{min-height:0}.reference-key ul{margin-bottom:12px}
/* Shared Math and Science learning components. */
.unit-ideas{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:14px 0}.unit-ideas h3{font-size:16px}.unit-ideas p{font-size:13px;line-height:1.85;margin-bottom:0}.unit-vocabulary{padding:15px 0 0;border-top:1px solid #b8cce4;margin-top:22px;font-size:13px}.unit-vocabulary summary{min-height:40px;font-weight:700;cursor:pointer}.unit-vocabulary dl{display:grid;grid-template-columns:1fr 1fr;gap:16px}.unit-vocabulary dt{font-weight:700}.unit-vocabulary dd{margin:4px 0 0;color:var(--muted);line-height:1.7}.model-section{background:linear-gradient(125deg,#e9f5f3,#f5f9ff)}.graph-model{display:grid;grid-template-columns:minmax(0,1fr) 180px;gap:16px;margin-top:12px}.graph-model svg{width:100%;height:auto;min-height:220px;background:var(--paper);border-radius:12px;padding:7px}.graph-model svg text{font-size:14px}.model-console{font-size:12px;background:var(--paper);padding:15px;border-radius:12px}.model-console label{display:grid;gap:6px;font-weight:700;margin-bottom:17px}.model-console input{width:100%;min-height:32px;accent-color:var(--blue)}.model-console output{color:var(--blue);font-size:19px}.model-equation{color:var(--blue);background:var(--soft);padding:10px;font-size:18px;font-weight:700;border-radius:8px}.model-console table{border-collapse:collapse;width:100%;text-align:center;font-size:12px}.model-console caption{margin:12px 0;font-size:11px}.model-console th,.model-console td{border-bottom:1px solid var(--line);padding:5px}.cell-model>svg,.water-model>svg{width:100%;height:auto;margin-top:15px;max-height:390px}.model-switch,.part-controls,.flow-controls{display:flex;flex-wrap:wrap;gap:7px;margin:10px 0}.model-switch button,.part-controls button,.flow-controls button{background:var(--paper);color:var(--ink);border:1px solid #bfd0e4;border-radius:9px;padding:10px 12px;font-size:11px;min-height:44px}.model-switch button[aria-pressed=true],.part-controls button[aria-pressed=true],.flow-controls button[aria-pressed=true]{background:#1464ed;color:white;border-color:#1464ed}.part-detail{background:var(--paper);border-left:3px solid #00967c;padding:17px 20px;border-radius:10px;margin-top:13px}.part-detail h3{font-size:17px}.part-detail p{font-size:13px;line-height:1.8;margin-bottom:0}.reasoned-example{background:var(--paper);border-radius:10px;padding:16px;margin:12px 0}.reasoned-example summary{font-size:14px;font-weight:700;cursor:pointer;min-height:40px}.reasoned-example ol{font-size:13px;line-height:1.85;padding-left:20px}.reasoned-example li{margin:12px 0}.unit-guided h2{font-size:21px;line-height:1.5}.unit-guided form{display:flex;gap:10px;align-items:end;flex-wrap:wrap;margin-top:20px}.unit-guided label{display:grid;gap:7px;font-size:12px}.unit-guided input{width:140px;border:1px solid #aec9c0;background:var(--paper);color:var(--ink);border-radius:8px;padding:10px;min-height:44px}.unit-guided-feedback,.unit-hint{font-size:13px;line-height:1.8}.unit-quiz fieldset{padding:0;border:0;margin:15px 0}.quiz-question{font-size:18px;font-weight:700;line-height:1.5;margin-bottom:15px}.quiz-options{display:grid;gap:9px}.quiz-options button{text-align:left;padding:14px 17px;min-height:48px;background:var(--paper);border:1px solid #bdcce1;border-radius:9px;color:var(--ink);font-size:13px}.quiz-options button:hover{border-color:var(--blue)}.quiz-feedback,.quiz-hint{font-size:13px;line-height:1.85}.quiz-count{font-size:12px;color:var(--muted)}.unit-connection{display:grid;grid-template-columns:160px 1fr;border-radius:13px;overflow:hidden;border:1px solid var(--line);margin:25px 0;background:var(--paper)}.unit-connection img{height:100%;width:100%;object-fit:cover}.unit-connection>div{padding:23px}.unit-connection h2{font-size:21px}.unit-connection p{font-size:13px;line-height:1.85;margin-bottom:0}.source-note{font-size:11px;color:var(--muted);line-height:1.7;padding:15px}.source-note a{text-decoration:underline}.cells-unit .numbered-heading>b{background:#008266}.water-unit .numbered-heading>b{background:#0086ad}.expanded-unit .immersive-heading h1{font-size:40px}.dark .model-section{background:#193831}.dark .unit-vocabulary{border-color:#3b5c70}
@media(max-width:1150px){.graph-model{grid-template-columns:minmax(0,1fr) 175px}.expanded-unit .immersive-heading h1{font-size:36px}}
@media(max-width:760px){.unit-ideas{grid-template-columns:1fr;gap:23px}.unit-vocabulary dl{grid-template-columns:1fr}.graph-model{grid-template-columns:1fr}.graph-model svg{min-height:0}.model-console{display:grid;grid-template-columns:1fr 1fr;gap:5px 15px}.model-console table,.model-console>p{grid-column:1/-1}.model-console label{min-width:0}.unit-guided{padding:20px}.unit-guided h2{font-size:19px}.unit-connection{grid-template-columns:1fr}.unit-connection img{height:140px}.unit-connection>div{padding:20px}.expanded-unit .immersive-heading h1{font-size:31px}.expanded-unit .immersive-heading{min-height:230px}.part-detail{padding:15px}.cell-model .quiet-caption{font-size:10px}}
@media(min-width:761px){.cell-model{display:grid;grid-template-columns:minmax(0,1fr) 155px;gap:8px 16px;align-items:center}.cell-model .model-switch{grid-column:1/-1}.cell-model>svg{grid-column:1;grid-row:2;max-height:300px}.cell-model>.quiet-caption{grid-column:1;grid-row:3}.cell-model .part-controls{grid-column:2;grid-row:2/4;display:grid;gap:6px}.cell-model .part-controls button{text-align:left}.cell-model .part-detail{grid-column:1/-1}.cell-model .part-controls button{padding:8px 10px;min-height:40px}}
.ratio-model,.percent-model,.fraction-model{margin-top:20px;font-size:13px;line-height:1.8}.ratio-model .range-label{display:grid;max-width:350px;gap:8px}.ratio-model input[type=range]{width:100%;min-height:36px;accent-color:var(--blue)}.ratio-bars{padding:20px;background:var(--paper);border-radius:12px;margin-top:18px}.ratio-bars>div+div{margin-top:15px}.cup-row{display:flex;flex-wrap:wrap;gap:4px;margin-top:9px}.cup{width:23px;height:27px;border-radius:3px 3px 7px 7px;display:block;border:1px solid #8dacc8}.cup.concentrate{background:#9861b6;border-color:#71448c}.cup.water{background:#66b9db;border-color:#328eaf}.model-results{padding:18px;background:var(--paper);border-radius:10px;margin:15px 0}.ratio-table{border-collapse:collapse;width:100%;font-size:12px;background:var(--paper);border-radius:9px}.ratio-table caption{padding:10px;font-weight:700}.ratio-table th,.ratio-table td{padding:8px;text-align:center;border-bottom:1px solid var(--line)}.selected-row{background:var(--soft);font-weight:700}.percent-controls,.fraction-controls{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px;margin:20px 0}.percent-controls label,.fraction-controls label{display:grid;gap:7px;align-content:start;font-size:12px;font-weight:700}.percent-controls input,.percent-controls select,.fraction-controls input,.fraction-controls select{width:100%;min-width:0;min-height:44px;padding:8px;background:var(--paper);color:var(--ink);border:1px solid #bccde0;border-radius:8px}.percent-controls input[type=range]{padding:0;accent-color:var(--blue)}.percent-grids{display:flex;gap:15px;flex-wrap:wrap;justify-content:center;background:var(--paper);border-radius:12px;padding:20px}.hundred-grid{display:grid;grid-template-columns:repeat(10,1fr);gap:3px;width:min(100%,230px);aspect-ratio:1}.hundred-grid span{background:#e9eef7;border:1px solid #c3cee0;border-radius:2px}.hundred-grid .filled{background:#1464ed;border-color:#1052c4}.fraction-picture{background:var(--paper);padding:16px;border-radius:11px;margin:15px 0;display:grid;gap:8px}.fraction-whole{display:grid;height:42px;border:2px solid #517699;border-radius:4px;overflow:hidden}.fraction-whole span{background:#e9eef7;border-right:1px solid #517699}.fraction-whole span:last-child{border:0}.fraction-whole .filled{background:#5a8ee0}.dark .hundred-grid span,.dark .fraction-whole span{background:#283e57}.dark .hundred-grid .filled,.dark .fraction-whole .filled{background:#679ff4}@media(max-width:760px){.percent-controls,.fraction-controls{grid-template-columns:1fr 1fr}.percent-controls label:last-child,.fraction-controls label:last-child{grid-column:1/-1}.ratio-table th,.ratio-table td{font-size:10px;padding:7px 4px}.ratio-bars{padding:15px}.cup{width:18px;height:23px}.hundred-grid{max-width:210px}.fraction-picture{padding:10px}.fraction-whole{height:36px}}
.physics-controls{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:18px 0}.physics-controls label{font-size:12px;font-weight:700;display:grid;gap:10px}.physics-controls input,.physics-controls select{min-height:44px;width:100%;min-width:0;border:1px solid #becfe3;border-radius:9px;background:var(--paper);color:var(--ink);padding:9px}.physics-controls input[type=range]{padding:0;accent-color:var(--blue)}.physics-model>svg{width:100%;height:auto;display:block;background:var(--paper);border-radius:13px;margin:15px 0;color:var(--ink)}.physics-result{background:var(--paper);padding:19px;border-left:3px solid #008d79;border-radius:10px;font-size:13px;line-height:1.85}.physics-model .quiet-caption{font-size:11px;line-height:1.7}.reference-unit .unit-companion .reference-key{background:var(--paper)}@media(max-width:540px){.physics-controls{gap:12px}.physics-controls label{font-size:11px}.physics-controls select{font-size:11px}.physics-result{padding:15px}}
@media(min-width:761px){.physics-model>svg{max-height:290px}.physics-model .physics-controls{margin:12px 0}.physics-model .physics-result{padding:14px 18px}}
@media(max-width:540px){.physics-model svg text{font-size:20px}}
/* Source-led lessons: the approved banner / topic rail / reading-column system. */
.optics-unit{grid-template-columns:190px minmax(0,1fr);gap:22px}.optics-rail nav{gap:2px}.optics-rail nav a{font-size:12px;min-height:49px;padding:8px 6px;gap:9px;line-height:1.45}.optics-rail nav b{font-size:10px;color:var(--muted);font-weight:600;flex-shrink:0}.optics-unit-link{display:block;font-weight:800;font-size:19px;line-height:1.4;margin-top:24px}.optics-heading{background-image:linear-gradient(90deg,#092536f2,#12394e93),url('/assets/pencil-photo.webp');background-position:center 46%;min-height:285px;padding-bottom:55px}.optics-heading h1{font-size:clamp(29px,3vw,44px);line-height:1.14;max-width:740px}.optics-heading .eyebrow{color:#c9e9ee;margin:17px 0 10px;font-size:10px;letter-spacing:1.5px}.optics-heading p{max-width:680px}.optics-unit .reference-columns{grid-template-columns:minmax(0,1fr) 210px}.optics-unit .reference-content{padding:0 21px 20px}.optics-prose{padding:25px 6px;scroll-margin-top:100px}.optics-prose h2{font-size:25px;line-height:1.3;margin:8px 0 15px}.optics-prose h3{font-size:19px;margin:27px 0 10px;line-height:1.4}.optics-prose p,.optics-example li,.optics-trap p{font-size:15px;line-height:1.85}.optics-prose p{margin:10px 0}.optics-prose .lead-explanation{font-size:17px;line-height:1.85}.optics-unit .unit-companion h2{font-size:16px;line-height:1.5}.optics-unit .unit-companion p,.optics-unit .unit-companion dd{font-size:12px;line-height:1.8}.optics-unit .unit-companion dt{font-weight:700;font-size:12px;margin:18px 0 4px}.optics-unit .unit-companion dd{margin:0;color:var(--muted)}.inline-notes{display:grid;grid-template-columns:43px minmax(0,1fr);gap:13px;padding:22px;background:#fff5e1;border:1px solid #e8d4ae;border-radius:13px;margin:8px 0 27px;color:#3e372c}.note-icon{border-radius:11px;background:#f7e5c2;color:#8c5510;width:40px;height:45px;display:grid;place-items:center}.inline-notes .section-kicker{color:#78501a;font-size:10px}.inline-notes h3{font-size:20px;line-height:1.4;margin:6px 0}.inline-notes p{font-size:13px;line-height:1.8;margin:8px 0}.note-actions{display:flex;flex-wrap:wrap;gap:8px 20px;align-items:center}.note-actions a,.note-actions button{min-height:44px;display:inline-flex;align-items:center;font-weight:700;color:#72450b;font-size:12px;text-decoration:underline}.pdf-slot object{width:100%;height:580px;display:block;margin-top:17px;background:white}.pdf-slot p{margin-bottom:0}.lesson-media{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.1fr);border:1px solid var(--line);border-radius:14px;overflow:hidden;margin:12px 0 28px;background:var(--paper)}.media-stage{background:radial-gradient(ellipse at 20% 10%,#2b5663,#0b283c);color:white;display:flex;flex-direction:column;justify-content:center;align-items:center;gap:16px;min-height:250px;position:relative}.media-stage>span:last-of-type{font-size:11px;letter-spacing:1px}.media-orbit{font-size:46px;font-weight:400;line-height:1;border:1px solid #89b6c780;border-radius:50%;width:76px;height:76px;display:grid;place-items:center}.media-stage button{font-size:12px;min-height:44px}.media-stage iframe{width:100%;height:100%;min-height:250px;border:0}.media-copy{padding:23px}.media-copy .section-kicker{font-size:10px;line-height:1.6}.media-copy h3{font-size:21px;line-height:1.35;margin:8px 0 13px}.media-copy p{font-size:13px;line-height:1.8}.media-copy a{font-size:12px;font-weight:700;color:var(--blue);min-height:44px;display:inline-flex;align-items:center}.media-copy small{display:block;color:var(--muted);font-size:11px;line-height:1.65}.optics-example{margin:20px 0;padding:20px;background:var(--paper);border-radius:10px}.optics-example h3{font-size:18px;line-height:1.5}.optics-example ol{padding-left:22px;margin-bottom:0}.optics-example li{padding:4px 0 4px 7px;font-size:14px}.optics-trap{padding:24px;border-left:4px solid #c68a34;background:#fff7e8;border-radius:0 12px 12px 0;margin-top:25px;color:#49341d}.optics-trap h3{font-size:19px;line-height:1.5;margin:12px 0}.optics-guided{border-top:1px solid var(--line);padding:0 0 24px}.optics-guided label{font-size:12px;display:block;color:var(--muted)}.optics-guided textarea{display:block;width:100%;resize:vertical;background:var(--paper);color:var(--ink);border:1px solid #b4c5d5;border-radius:9px;padding:14px;margin:8px 0 15px;font:inherit;line-height:1.7}.optics-guided summary{cursor:pointer;font-size:13px;font-weight:700;padding:12px 0;min-height:44px}.optics-guided details p{font-size:14px;padding:0 10px}.optics-practice{background:#edf7f3;border-radius:13px;padding:24px;color:#173c35}.optics-question{border-top:1px solid #bedacc;padding:24px 0 8px}.optics-question fieldset{border:0;padding:0;margin:0 0 15px;min-width:0}.optics-question legend{font-size:16px;font-weight:700;line-height:1.6;margin-bottom:17px}.optics-question label{display:flex;align-items:start;gap:12px;font-size:14px;line-height:1.65;background:white;border:1px solid #c2d6ce;border-radius:9px;padding:12px;margin:8px 0;min-height:48px;color:#25423a;cursor:pointer}.optics-question input{margin-top:5px;flex-shrink:0;accent-color:#00765f;width:17px;height:17px}.optics-question .primary{background:#006f57;font-size:12px}.question-feedback{padding:0;font-size:14px!important}.question-feedback:not(:empty){padding:15px;border-radius:8px;background:#fff}.question-feedback.needs-thinking{border-left:3px solid #a96513}.question-feedback.is-correct{border-left:3px solid #007256}.optical-model{background:#fff;border:1px solid #cee0ed;border-radius:12px;margin-top:10px;padding:18px;color:#203e59}.optical-controls{display:flex;gap:16px;flex-wrap:wrap;align-items:end}.optical-controls label{display:grid;gap:10px;min-width:150px;flex:1;font-size:12px;font-weight:600}.optical-controls output{font-weight:800;color:#0759b4}.optical-controls input:not([type=checkbox]),.optical-controls select{width:100%;min-height:44px;font:inherit;border:1px solid #b7cada;border-radius:7px;padding:8px;background:white;color:#203e59}.optical-controls input[type=range]{padding:0;accent-color:#1766ce}.optical-controls fieldset{display:flex;gap:20px;flex-wrap:wrap;padding:12px;border:1px solid #bfd1df;border-radius:8px}.optical-controls fieldset label{display:flex;align-items:center;min-width:0;flex:auto;min-height:44px}.optical-controls input[type=checkbox]{width:21px;height:21px;accent-color:#1766ce}.optical-model svg{width:100%;height:auto;margin-top:15px;overflow:hidden;display:block}.optical-model .physics-result{font-size:14px;line-height:1.8;background:#eef5fb;border-radius:8px;padding:15px}.optical-model .quiet-caption{font-size:11px;line-height:1.7;text-align:left}.simulation-invite,.playlist-invite{padding:25px;background:#eaf4f3;border:1px solid #c6deda;border-radius:13px;margin:22px 0;color:#224640}.simulation-invite{display:flex;gap:18px}.sim-symbol{font-size:32px}.simulation-invite h3,.playlist-invite h3{font-size:20px;line-height:1.4;margin:9px 0}.simulation-invite p,.playlist-invite p{font-size:14px;line-height:1.85}.simulation-invite .secondary,.playlist-invite .secondary{font-size:12px;background:white;color:#16534a}.playlist-source{display:block;min-height:44px;line-height:44px;font-size:12px;text-decoration:underline}.lesson-photo,.lesson-source-image{margin:22px 0 28px}.lesson-photo img{width:100%;height:310px;object-fit:cover;border-radius:13px}.lesson-source-image{background:#fff;border:1px solid #d8e2e9;border-radius:12px;padding:16px}.lesson-source-image img{width:100%;height:auto;max-height:350px;object-fit:contain}.lesson-photo figcaption,.lesson-source-image figcaption{font-size:12px;line-height:1.8;color:var(--muted);padding-top:13px}.optics-next{display:grid;grid-template-columns:1fr 1fr;gap:15px;margin-top:22px}.optics-next a{padding:20px;border:1px solid var(--line);border-radius:12px;font-size:14px;font-weight:700;display:flex;align-items:center;justify-content:space-between;gap:15px;color:var(--blue);line-height:1.5}.optics-directory>a{display:flex;align-items:center;gap:17px;padding:24px 0;border-bottom:1px solid var(--line)}.optics-directory>a>b{font-size:13px;color:#1464bd;background:#e9f3ff;border-radius:10px;min-width:39px;height:44px;display:grid;place-items:center}.optics-directory>a>span{margin-left:auto;font-size:22px;color:#257361}.optics-directory h3{font-size:18px;margin:0 0 5px}.optics-directory p{font-size:13px;line-height:1.7;margin:0;color:var(--muted)}.light-journey{display:flex;align-items:center;gap:20px;justify-content:space-evenly;background:linear-gradient(135deg,#e8f4ff,#eff9f5);padding:25px 10px;border-radius:12px;margin:25px 0;color:#25485d}.light-journey>span{display:flex;flex-direction:column;text-align:center;font-size:35px;gap:10px}.light-journey b{font-size:15px}.light-journey small{font-size:11px}.light-journey i{font-size:26px;font-style:normal}.refraction-feature{position:relative;border-radius:14px;overflow:hidden;margin:20px 0;color:white;min-height:340px;display:flex;align-items:center}.refraction-feature img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;filter:brightness(.45)}.refraction-feature>div{position:relative;padding:32px;max-width:440px}.refraction-feature h2{font-size:30px;color:white;line-height:1.2;margin:12px 0}.refraction-feature p{font-size:14px;line-height:1.8}.refraction-feature .section-kicker{color:#c5f1ee}.optics-picker{display:none}.optics-unit :is(section,aside)[id]{scroll-margin-top:100px}
[data-theme=dark] .optics-prose.optics-practice{background:#16382e;color:#e0f4e9}[data-theme=dark] .optics-example{background:#152d43}
@media(min-width:1500px){.optics-unit .reference-columns{grid-template-columns:minmax(0,1fr) 225px}.optics-unit .reference-content{padding-left:30px;padding-right:30px}}
@media(max-width:1150px){.optics-unit .reference-columns{grid-template-columns:1fr}.optics-unit .unit-companion{display:none}.optics-unit{grid-template-columns:170px minmax(0,1fr)}.optics-prose{padding-left:10px;padding-right:10px}}
@media(max-width:1000px){.optics-unit{display:block}.optics-rail{display:none}.optics-picker{display:flex;align-items:center;gap:12px;justify-content:space-between;font-size:12px;font-weight:700;margin:5px 0 17px}.optics-picker select{max-width:73%;min-height:44px;border:1px solid var(--line);border-radius:8px;padding:8px;background:var(--paper);color:var(--ink);font:inherit}.optics-heading h1{font-size:37px}.optics-unit .reference-columns{margin-left:12px;margin-right:12px}}
@media(max-width:600px){.optics-heading{min-height:285px;padding:23px 23px 48px}.optics-heading h1{font-size:31px}.optics-heading p{font-size:14px}.optics-unit .reference-content{padding:0 14px 15px}.optics-unit .reference-columns{margin-left:6px;margin-right:6px}.optics-unit .learning-tabs{grid-template-columns:repeat(3,1fr)}.optics-unit .learning-tabs a{font-size:11px;min-height:44px}.optics-prose{padding:23px 0}.optics-prose h2{font-size:23px}.optics-prose .lead-explanation{font-size:16px}.optics-prose p{font-size:15px;line-height:1.85}.inline-notes{grid-template-columns:1fr;padding:20px;gap:10px}.note-icon{display:none}.inline-notes h3{font-size:19px}.lesson-media{grid-template-columns:1fr}.media-stage{min-height:230px}.media-stage iframe{aspect-ratio:16/9;min-height:210px}.optics-unit .reference-block{padding:17px 12px}.optics-unit .numbered-heading h2{font-size:21px}.optical-model{padding:12px}.optical-controls{gap:12px}.optical-controls label{min-width:130px}.optical-model svg text{font-size:17px}.optics-example{padding:16px 12px}.optics-trap{padding:20px}.optics-prose.optics-practice{padding:20px 15px}.optics-next{grid-template-columns:1fr}.light-journey{gap:8px;padding:23px 6px}.light-journey small{font-size:10px}.optics-directory>a{gap:12px}.optics-directory h3{font-size:17px}.optics-directory p{font-size:12px}.optics-directory>a>b{min-width:32px}.lesson-photo img{height:240px}.refraction-feature>div{padding:25px}.pdf-slot object{height:420px}}
.optics-heading.eye-heading{background-image:linear-gradient(90deg,#092536f5,#17354fb5),url('/assets/optics-eye-detail.webp');background-position:center 45%}.optics-heading.sun-heading{background-image:linear-gradient(90deg,#092536eb,#12394e50),url('/assets/alpine-sunrise.webp');background-position:center 50%}
/* Classroom first: notes, authentic achievement indicators and named projects. */
.unit-entry{padding:23px 7px 18px;border-bottom:1px solid var(--line)}.unit-indicators{border:1px solid #88a8c5;border-radius:10px;padding:15px 18px;margin-bottom:21px;background:#f5faff}.unit-indicators .section-kicker{font-size:9px;color:#49627d;display:block;margin-bottom:5px}.unit-indicators>a{font-size:14px;line-height:1.6;font-weight:750;color:#194e84;display:flex;justify-content:space-between;gap:12px;align-items:center;min-height:36px}.entry-notes h2{font-size:18px;line-height:1.4;margin:0 0 10px}.entry-notes nav{display:flex;flex-wrap:wrap;gap:0 20px}.entry-notes a{display:inline-flex;align-items:center;gap:8px;min-height:44px;font-size:12px;font-weight:600;color:var(--blue);text-decoration:underline;text-underline-offset:4px;line-height:1.6;max-width:100%}.entry-notes a span{font-size:10px}.unit-projects{display:grid;grid-template-columns:1fr 1fr;gap:15px;padding:24px 0 14px}.named-project{padding:21px 18px;border:1px solid #c7d3e5;border-top:3px solid #7960aa;border-radius:12px;background:#faf8ff;scroll-margin-top:100px;color:#29374b}.named-project.salary-project{border-color:#b8d4c4;border-top-color:#258265;background:#f2f9f5}.project-title{display:flex;gap:10px;align-items:center}.project-title>span{display:grid;place-items:center;min-width:37px;height:37px;border-radius:8px;background:#ece6f8;color:#61468c;font-size:13px;font-weight:800}.salary-project .project-title>span{font-size:24px;background:#deeee3;color:#176b4e}.named-project h2{font-size:20px;line-height:1.3;margin:0}.named-project>p{font-size:12px;line-height:1.7;color:#4d6174;margin:13px 0}.named-project nav{display:grid;gap:0}.named-project nav a{font-size:12px;line-height:1.65;display:flex;justify-content:space-between;gap:10px;align-items:center;border-top:1px solid #d6deea;padding:11px 0;min-height:44px;color:#274b7a;font-weight:600}.named-project nav a:hover,.entry-notes a:hover{text-decoration:underline}.salary-project nav a{border-color:#cfe2d7;color:#1b624e}[data-theme=dark] .unit-indicators{background:#142e46;border-color:#537898}[data-theme=dark] .unit-indicators>a{color:#cce6ff}[data-theme=dark] .unit-indicators .section-kicker{color:#bdd7ef}
@media(max-width:700px){.unit-projects{grid-template-columns:1fr}.unit-entry{padding:21px 2px 16px}.unit-indicators{padding:14px}.unit-indicators>a{font-size:14px}.entry-notes nav{gap:0 16px}.entry-notes a{font-size:12px}.named-project{padding:20px}.named-project nav a{font-size:13px}}
/* Linear Relations: one reference system, hub plus focused teaching pages. */
.linear-pathway .immersive-heading h1{font-size:clamp(29px,3vw,47px);line-height:1.15}.linear-pathway .unit-companion nav a{font-size:12px;line-height:1.5;min-height:44px;align-items:center}.linear-pathway .unit-companion .reference-key>a{display:block;min-height:44px;padding:10px 0}.linear-pathway .unit-companion nav a[aria-current]{color:#0757cf;background:#e6efff;border-radius:7px}.linear-pathway .learning-tabs{scroll-margin-top:90px}.hub-jumps{display:flex;flex-wrap:wrap;gap:0 20px;border-bottom:1px solid var(--line);padding:9px 4px}.hub-jumps a{display:inline-flex;align-items:center;min-height:44px;font-size:12px;color:var(--blue);font-weight:700}.linear-lesson-list{margin-top:18px}.linear-lesson-list>a{display:flex;align-items:center;gap:16px;padding:20px 0;border-bottom:1px solid var(--line)}.linear-lesson-list>a>b{display:grid;place-items:center;background:#e7f1ff;color:#0757c4;border-radius:10px;min-width:39px;height:43px;font-size:13px}.linear-lesson-list strong{font-size:17px;line-height:1.5;display:block}.linear-lesson-list small{font-size:12px;line-height:1.7;color:var(--muted);display:block;margin-top:5px}.linear-lesson-list .icon{margin-left:auto;min-width:20px;color:var(--blue)}.learning-collection{border-top:1px solid var(--line);padding:26px 0 20px;margin-top:13px}.collection-brand{display:flex;align-items:center;gap:15px;margin:0 0 17px}.collection-brand>b{display:grid;place-items:center;background:#e6f0ff;color:#0757bd;min-width:47px;height:49px;border-radius:12px;font-size:21px}.khan-collection .collection-brand>b{background:#dff2ec;color:#00725f}.video-collection .collection-brand>b{background:#fbe7e5;color:#9f3429}.geogebra-collection .collection-brand>b{background:#ede7fa;color:#7043af}.collection-brand h3{margin:3px 0!important;font-size:22px!important}.collection-brand .section-kicker{font-size:9px}.learning-collection nav{display:flex;flex-wrap:wrap;gap:0 24px}.learning-collection nav a{font-size:13px;min-height:44px;display:inline-flex;align-items:center;color:var(--blue);font-weight:600;text-decoration:underline;text-underline-offset:4px;line-height:1.7}.learning-collection>p{font-size:13px;color:var(--muted)}.hub-simulations{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px;margin:18px 0}.hub-simulations a{display:block;min-width:0}.hub-simulations img{display:block;width:100%;height:auto;aspect-ratio:1.62;object-fit:cover;border:1px solid var(--line);border-radius:9px}.hub-simulations strong{display:block;font-size:12px;line-height:1.7;margin-top:10px;color:var(--ink)}.hub-simulations a>span{font-size:11px;line-height:1.7;color:var(--muted);display:block;margin-top:5px}.hub-original{padding:20px 8px;font-size:12px;line-height:1.8;color:var(--muted);border-top:1px solid var(--line)}.lesson-target{font-size:13px!important;border-left:3px solid #19755f;background:#edf7f2;padding:14px 16px;border-radius:0 9px 9px 0;color:#234d42}.linear-model{background:#fff;color:#234059;border:1px solid #c8daea;border-radius:12px;padding:20px;margin:13px 0}.lm-drawing{margin-top:23px}.lm-drawing svg{display:block;width:100%;height:auto}.lm-drawing svg text{font:14px Arial;fill:#27445c}.linear-model .physics-result{font-size:14px;line-height:1.8;padding:16px;background:#eef5fb;border-radius:9px}.tile-tray{display:flex;flex-wrap:wrap;align-items:center;gap:8px;padding:17px;border:1px dashed #91abc1;border-radius:10px;min-height:88px;background:#f7fafc}.algebra-tile{display:inline-flex;justify-content:center;align-items:center;border:2px solid;border-radius:4px;font-size:15px;font-weight:700;min-height:36px}.algebra-tile.positive{background:#e4f0ff;border-color:#1464bd;color:#12549a}.algebra-tile.negative{background:#ffebe6;border-color:#ad4934;color:#872d21}.x-tile{width:75px}.unit-tile{width:36px}.tile-equation{font-size:26px;font-weight:700;text-align:center;padding:15px 0;color:#1a4e88}.tile-groups{display:grid;gap:10px}.balance-steps{list-style:none;margin:0;padding:0}.balance-steps li{padding:16px 0;border-bottom:1px solid #d7e2eb}.balance-steps span{display:block;font-size:12px;color:#4a6378;margin-bottom:8px}.balance-steps strong{font-size:23px;line-height:1.5;overflow-wrap:anywhere}.linear-model table{width:100%;border-collapse:collapse;font-size:14px;margin-top:20px}.linear-model caption{text-align:left;font-weight:700;margin-bottom:10px}.linear-model th,.linear-model td{padding:10px;border:1px solid #b9cede;text-align:center}.linear-model .quiet-caption{line-height:1.8;text-align:left}
@media(max-width:1000px){.linear-pathway{display:block}.linear-rail{display:none}.linear-pathway .optics-picker{display:flex}}
@media(max-width:600px){.linear-pathway .immersive-heading{padding:24px 23px 45px}.linear-pathway .immersive-heading h1{font-size:31px}.linear-pathway .reference-content{padding:0 15px 20px}.linear-pathway .reference-columns{margin-left:6px;margin-right:6px}.linear-pathway .learning-tabs{grid-template-columns:repeat(3,1fr)}.linear-pathway .learning-tabs a{font-size:11px;min-height:44px}.linear-lesson-list strong{font-size:16px}.linear-lesson-list small{font-size:12px}.linear-lesson-list>a{gap:12px}.hub-simulations{grid-template-columns:1fr 1fr;gap:17px}.hub-simulations a:last-child{grid-column:1/-1;max-width:210px}.collection-brand h3{font-size:20px!important}.collection-brand .section-kicker{line-height:1.6}.linear-model{padding:13px}.linear-model .optical-controls label{min-width:110px}.tile-equation{font-size:22px}.hub-jumps{gap:0 17px}.hub-jumps a{font-size:11px}}
.watch-invite{display:flex;align-items:start;gap:18px;background:#f0f6fb;border:1px solid #cfdfec;padding:24px;border-radius:13px;margin:15px 0 30px}.watch-invite>span{display:grid;place-items:center;min-width:48px;height:48px;background:#deebe5;color:#176450;border-radius:50%;font-size:27px}.watch-invite h3{font-size:21px;margin:8px 0}.watch-invite p{font-size:14px;line-height:1.85}.watch-invite a{font-size:13px;font-weight:700;color:#125a9d;display:inline-flex;align-items:center;min-height:44px}.watch-invite .section-kicker{font-size:10px}.hub-jumps{scroll-margin-top:90px}.entry-notes{scroll-margin-top:90px}
@media(max-width:600px){.watch-invite{padding:20px;gap:12px}.watch-invite>span{min-width:34px;height:34px;font-size:20px}.watch-invite h3{font-size:19px}}
.linear-values{grid-column:1/-1;background:var(--paper);border-radius:11px;padding:12px 18px}.linear-values summary{cursor:pointer;font-size:13px;font-weight:700;min-height:44px;display:list-item;padding:12px 0}.linear-values table{width:100%;border-collapse:collapse;font-size:13px}.linear-values caption{text-align:left;font-size:11px;color:var(--muted);padding:8px 0}.linear-values th,.linear-values td{border-bottom:1px solid var(--line);padding:8px;text-align:center}.linear-values table thead{background:#edf4fc;color:#264663}
/* Resource groups use a shared visual centre; instructional reading stays aligned. */
.unit-entry{text-align:center}.entry-notes nav{justify-content:center;column-gap:24px}.unit-indicators>a{justify-content:center;text-align:center}.named-project{text-align:center}.project-title{justify-content:center}.named-project nav a{justify-content:center;text-align:center}.learning-collection{text-align:center}.collection-brand{justify-content:center;text-align:center}.learning-collection nav{justify-content:center;column-gap:24px}.learning-collection>p{max-width:580px;margin-left:auto;margin-right:auto}.hub-simulations{justify-content:center}.hub-simulations a{text-align:center}.hub-simulations img{margin-left:auto;margin-right:auto}
@media(max-width:600px){.entry-notes nav,.learning-collection nav{column-gap:18px}.named-project nav a{padding-left:5px;padding-right:5px}.collection-brand{gap:12px}.hub-simulations a:last-child{justify-self:center;width:100%}}
/* Recognisable source marks sit beside the name without adding a second badge. */
.collection-brand .source-brand-icon{display:block;width:36px;height:36px;object-fit:contain;flex-shrink:0;border-radius:0;background:transparent}.collection-brand .source-brand-icon.brand-wide{width:55px;height:37px}.collection-brand{gap:12px}.collection-brand>div{min-width:0}.source-brand-icon{color-scheme:light}

/* Reference refinement: confident hierarchy, readable resources, quiet surfaces. */
:root:not(.dark){--ink:#0d2144;--muted:#50617b;--shadow:0 4px 18px #203c640d}
.reference-content{box-shadow:0 5px 24px #243e6508;border-color:#e5ecf5;padding-left:20px;padding-right:20px}
.immersive-heading{background-position:center 44%;padding:30px 34px 60px}
.linear-pathway .immersive-heading h1{font-size:clamp(35px,4vw,55px);letter-spacing:-.045em;line-height:1.1}
.immersive-heading p{font-size:17px;max-width:640px;line-height:1.6}
.subject-rail nav a{font-size:13px;line-height:1.4;gap:11px;padding:10px 8px}
.subject-rail .unit-symbol{font:700 25px/1 Arial,sans-serif;width:36px;height:39px;box-shadow:inset 0 1px 0 #ffffff40,0 3px 8px #17345112}
.subject-rail nav a .unit-symbol.mark-blue{background:linear-gradient(145deg,#2486ff,#0055eb)}
.subject-rail nav a .unit-symbol.mark-coral{background:linear-gradient(145deg,#ff6577,#e2355b)}
.subject-rail nav a .unit-symbol.mark-teal{background:linear-gradient(145deg,#00b7ab,#008979)}
.subject-rail nav a .unit-symbol.mark-amber{background:linear-gradient(145deg,#ffbd37,#dc8600)}
.subject-rail nav a .unit-symbol.mark-violet{background:linear-gradient(145deg,#a55eff,#7733dc)}
.unit-companion nav a{font-size:13px;line-height:1.5}
.linear-pathway .unit-companion nav a{font-size:13px}
.unit-companion section{box-shadow:0 4px 16px #203c6407}
.reference-unit .learning-tabs a{font-size:12px;min-height:48px;gap:7px}
.hub-jumps{justify-content:center;gap:0 22px;padding:10px 0 12px}
.hub-jumps a{font-size:13px;min-height:44px}
.entry-notes h2{font-size:23px}
.entry-notes a{font-size:14px;line-height:1.65}
.entry-notes nav{gap:3px 23px}
.unit-indicators{border:1px solid #bcd1e4;background:linear-gradient(120deg,#edf6ff,#f6fbff);border-radius:12px}
.unit-indicators>a{font-size:15px}
.unit-indicators .section-kicker{font-size:10px;letter-spacing:.1em}
.named-project{padding:23px 19px 17px;border-top-width:3px;box-shadow:0 3px 12px #203c6407}
.named-project h2{font-size:21px;letter-spacing:-.035em}
.named-project nav a{font-size:14px;padding:12px 0;line-height:1.6}
.named-project>p{font-size:13px}
.linear-lesson-list{display:grid;grid-template-columns:1fr 1fr;column-gap:25px}
.linear-lesson-list>a{padding:19px 0;align-items:flex-start;gap:12px}
.linear-lesson-list>a>b{min-width:32px;height:36px;border-radius:9px;font-size:12px}
.linear-lesson-list strong{font-size:16px;line-height:1.4}
.linear-lesson-list small{font-size:13px;line-height:1.65}
.linear-lesson-list .icon{width:16px;min-width:16px;margin-top:7px}
.learning-collection{padding:32px 18px;margin-top:20px;border:1px solid #e1e9f1;border-radius:14px;background:linear-gradient(135deg,#fafcff,#fff)}
.learning-collection.khan-collection{background:linear-gradient(135deg,#f1faf6,#fff);border-color:#d7e9df}
.learning-collection.geogebra-collection{background:linear-gradient(135deg,#f7f4ff,#fff);border-color:#e5ddf2}
.learning-collection.video-collection{background:linear-gradient(135deg,#fff8f6,#fff);border-color:#f1e2dd}
.learning-collection nav a{font-size:14px;line-height:1.7;padding:4px 0}
.collection-brand{margin-bottom:17px;gap:12px}
.collection-brand .section-kicker{font-size:10px;letter-spacing:.08em}
.learning-collection>p{font-size:14px;line-height:1.75}
.hub-simulations strong{font-size:14px;line-height:1.5}
.hub-simulations a>span{font-size:12px;line-height:1.65}
.connection-preview{padding:0!important;overflow:hidden}
.connection-preview>img{width:100%;height:138px;object-fit:cover;display:block}
.connection-preview>div{padding:17px}
.connection-preview h2{font-size:18px;line-height:1.3;margin:8px 0}
.connection-preview p{font-size:13px;line-height:1.7}
.connection-preview a{font-size:13px;color:#0757cf;font-weight:700;display:block;line-height:1.6;padding:9px 0}
.connection-preview .section-kicker{font-size:9px}
.reference-block{border:1px solid #e3ecf880;padding:24px}
.optics-prose p,.optics-example li,.optics-trap p{font-size:16px;line-height:1.8}
.reference-block h2{letter-spacing:-.035em}
.advertising-break{clear:both;margin:52px 0;padding:20px 0 24px;border-top:1px solid #e4eaf1;border-bottom:1px solid #e4eaf1;text-align:center;background:#f8fafc;color:#65728a;width:100%;break-inside:avoid}
.ad-label{display:block;font-size:10px;letter-spacing:.1em;text-transform:uppercase;margin:0 0 12px;line-height:1.5}
.ad-preview{height:90px;max-width:728px;margin:auto;display:flex;flex-direction:column;justify-content:center;align-items:center;background:#eff3f7;border:1px dashed #ccd6e1;font-size:13px;gap:3px}
.ad-preview small{font-size:11px;color:#64718a}
.advertising-break .adsbygoogle{width:100%;height:90px}
@media(min-width:1500px){.shell,.nav-inner{max-width:1440px}.reference-unit{grid-template-columns:210px minmax(0,1fr);gap:25px}.reference-columns{grid-template-columns:minmax(0,1fr) 245px}}
@media(max-width:1150px){.reference-content{padding-left:18px;padding-right:18px}}
@media(max-width:760px){.linear-lesson-list{grid-template-columns:1fr}.reference-unit .learning-tabs{gap:2px}.reference-unit .learning-tabs a{font-size:11px;gap:5px}.reference-content{padding-left:16px;padding-right:16px}.linear-pathway .immersive-heading h1{font-size:34px}.learning-collection{padding:27px 16px}.advertising-break{margin:40px 0;padding:20px 0 24px}.ad-preview,.advertising-break .adsbygoogle{height:100px}.named-project nav a,.entry-notes a{font-size:14px}.hub-jumps a{font-size:12px}.hub-simulations{gap:15px}.hub-simulations strong{font-size:13px}}
@media(max-width:540px){.reference-unit .learning-tabs{grid-template-columns:repeat(3,1fr)}.linear-pathway .immersive-heading{padding:25px 23px 47px}.immersive-heading p{font-size:15px}.named-project h2{font-size:22px}.named-project nav a{padding:12px 0}.learning-collection nav{gap:3px 20px}.collection-brand h3{font-size:21px!important}.optics-prose p,.optics-example li,.optics-trap p{font-size:16px;line-height:1.8}.reference-block{padding:18px}.hub-simulations a:last-child{justify-self:center}}
.dark .learning-collection{background:#172b40;border-color:#3b5066}.dark .learning-collection.khan-collection{background:#18332f}.dark .learning-collection.geogebra-collection{background:#27243e}.dark .learning-collection.video-collection{background:#352a29}.dark .advertising-break{background:#182a3b;border-color:#3b5066}.dark .ad-preview{background:#20354a;border-color:#526981;color:#c6d6e6}.dark .ad-preview small{color:#a8bed3}.dark .unit-indicators{background:#19384d;border-color:#526e88}.dark .unit-indicators>a{color:#c2deff}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;transition:none!important}}
@media print{.advertising-break{display:none!important}}
.lesson-purpose{font-size:13px;color:#42617a;border-bottom:1px solid #e5ebf2;padding-bottom:12px;margin-bottom:20px}
.lesson-purpose summary{cursor:pointer;min-height:44px;display:list-item;padding:10px 0;font-weight:600}
.lesson-purpose p{font-size:14px}
.linear-pathway #learn{padding-top:20px;padding-bottom:12px}
.linear-pathway #learn .section-kicker{font-size:10px}
.linear-pathway #model{margin-top:0}
.subject-rail nav a .unit-symbol.mark-amber{color:#513000}
.subject-rail nav a .unit-symbol.mark-coral{color:#64142b}
.subject-rail nav a .unit-symbol.mark-teal{background:linear-gradient(145deg,#00978b,#00786e)}
.dark .ad-label{color:#b7c8d8}
/* Viewable manual placements: quiet in-flow banners and a separate desktop slot. */
.advertising-break{margin:38px 0;padding:18px 0 22px}
.advertising-side{display:none}
@media(min-width:1280px){.unit-companion .advertising-side{display:block;position:static;padding:16px 12px 20px;margin:32px 0;min-width:0;width:100%;border:1px solid #e4eaf1;border-radius:12px;background:#f8fafc;box-shadow:none}.advertising-side .ad-preview{width:100%;height:200px;max-width:300px}.advertising-side .adsbygoogle{height:200px}.advertising-side .ad-label{margin-bottom:12px}}
@media(max-width:760px){.advertising-break{margin:36px 0;padding:18px 0 22px}.advertising-side{display:none!important}}
.dark .unit-companion .advertising-side{background:#182a3b;border-color:#3b5066}
@media print{.unit-companion .advertising-side{display:none!important}}
/* Linear Relations: classroom identity and deeper learning. */
.project-brand-heading{display:flex;align-items:center;justify-content:center;min-height:80px;background:#fff;border-radius:8px;padding:8px}
.project-brand-heading img{display:block;width:100%;height:auto;max-height:72px;object-fit:contain}
.named-project.algebra-boot-camp{background:#fffaf9;border-top-color:#c82e3b}
.named-project.salary-project{background:#f6fbf7}
.named-project .project-guide-link{display:block;color:#0757cf;font-size:14px;font-weight:700;min-height:44px;padding:10px 0;margin-bottom:8px}
.learning-collection h4{font-size:15px;letter-spacing:-.01em;margin:24px 0 10px}
.learning-collection h4:not(:first-of-type){border-top:1px solid #dbe9e2;padding-top:25px}
.project-guide-brand{display:block;width:100%;height:auto;max-height:140px;object-fit:contain;margin:0 auto 25px;background:white;border-radius:8px;padding:12px}
.linear-vocabulary{margin:5px 5px 25px}.linear-vocabulary summary{min-height:44px;padding:13px 15px}
.linear-pathway .inline-notes:has(.note-preview){grid-template-columns:115px minmax(0,1fr);align-items:start;background:#fffaf0}
.note-preview{display:block;background:white;border:1px solid #ddcfb8;border-radius:7px;overflow:hidden;box-shadow:0 3px 10px #6c543512}
.note-preview img{display:block;width:100%;height:auto;aspect-ratio:3/4;object-fit:cover;object-position:top}
.linear-challenge{background:linear-gradient(120deg,#eef8f4,#f7fbff);border:1px solid #d6e7df;border-radius:14px;padding:26px;margin:28px 0}
.linear-challenge h2,.linear-challenge h3{font-size:22px;line-height:1.4;margin:7px 0 12px}
.linear-challenge p{font-size:15px;line-height:1.8}.linear-challenge a{font-size:14px;color:#0757cf;font-weight:700;display:inline-flex;min-height:44px;align-items:center}
.linear-practice{padding:26px;background:linear-gradient(135deg,#edf7ff,#f4faf7);border:1px solid #cbdfe9;border-radius:14px;margin:24px 0 35px}
.linear-practice>h3{font-size:23px!important;margin:7px 0 12px!important;line-height:1.35}
.linear-practice p{font-size:14px;line-height:1.8}.linear-practice .lp-content h3{font-size:20px;line-height:1.6;margin:12px 0 20px}
.lp-progress{display:flex;flex-wrap:wrap;align-items:center;gap:12px;font-size:12px;margin:23px 0;padding-bottom:22px;border-bottom:1px solid #cddde6}
.lp-meter{accent-color:#00836b;height:9px;width:140px;border:0;border-radius:10px;overflow:hidden}.lp-meter::-webkit-progress-bar{background:#dce7ef}.lp-meter::-webkit-progress-value{background:#00836b}
.lp-fields{display:flex;flex-wrap:wrap;gap:15px}.lp-fields label{display:grid;gap:7px;font-size:14px;font-weight:700;flex:1;min-width:140px}
.lp-fields input{width:100%;min-height:47px;border-radius:9px;border:1px solid #9eb8cb;background:var(--paper);color:var(--ink);padding:10px 13px;min-width:0}
.lp-actions{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:16px 0}.lp-actions button{font-size:13px;min-height:44px}
.lp-feedback:empty,.lp-solution:empty,.lp-hints:empty{display:none}.lp-feedback{font-weight:650;color:#185f55;padding:15px 0}
.lp-hints p{border-left:3px solid #879fd3;background:#ffffffb8;padding:12px 15px;border-radius:0 8px 8px 0}
.lp-solution{background:var(--paper);padding:19px;border-radius:10px;border:1px solid #d7e3eb;margin:15px 0}.lp-solution h4{font-size:16px}.lp-solution li{font-size:14px;line-height:1.8;margin:8px 0}.lp-solution ol{padding-left:20px}
.concept-check-title{border-top:1px solid var(--line);padding-top:25px;margin-top:30px!important}
.linear-studio{background:var(--paper);border:1px solid #d3e1ec;border-radius:12px;padding:22px;margin:20px 0;color:var(--ink)}
.linear-studio h3{font-size:21px;line-height:1.4}.linear-studio p{font-size:14px;line-height:1.8}
.linear-studio label{display:grid;gap:8px;font-size:13px;font-weight:700}.linear-studio input{width:100%;min-width:0;min-height:44px;accent-color:#1464ed}
.linear-studio input[type=number]{border:1px solid #b3c7d7;border-radius:8px;background:var(--paper);color:var(--ink);padding:10px}
.linear-studio output{font-size:22px;color:#1464ed}
.studio-controls{display:grid;grid-template-columns:1fr 1fr;gap:17px}
.studio-drawing svg{width:100%;height:auto;display:block;margin-top:17px}.studio-drawing svg text{font:13px Arial,sans-serif;fill:#304d68}
.studio-result{background:#eaf3ff;padding:16px 18px;border-radius:9px;line-height:1.8;margin:18px 0 0}
.studio-table-wrap{overflow-x:auto;margin-top:20px}.linear-studio table{border-collapse:collapse;width:100%;font-size:13px;margin-top:18px}.linear-studio th,.linear-studio td{padding:11px 8px;border-bottom:1px solid #d7e2eb;text-align:right;vertical-align:top}.linear-studio th:first-child,.linear-studio td:first-child{text-align:left}.linear-studio caption{text-align:left;font-size:13px;line-height:1.6;margin-bottom:12px;font-weight:700}.linear-studio th{font-size:12px;line-height:1.6;background:#f0f6fc}.studio-table-wrap table{min-width:450px}
.studio-bridge{margin:30px 0 10px;font-size:20px}
.bootcamp-days article{display:flex;gap:19px;padding:25px 5px;border-bottom:1px solid var(--line)}.bootcamp-days article>b{display:grid;place-items:center;width:42px;height:44px;flex-shrink:0;background:#fff0ee;color:#b22d3b;border-radius:10px;font-size:18px}.bootcamp-days h2{font-size:24px;margin:7px 0}.bootcamp-days p{font-size:15px;line-height:1.8}.bootcamp-days a,.project-file-list a{font-size:14px;color:#0757cf;min-height:44px;display:flex;align-items:center;line-height:1.6}.project-file-list{display:grid;gap:5px}.project-file-list a{border-bottom:1px solid var(--line);padding:13px 0}
.dark .linear-practice,.dark .linear-challenge{background:#183346;border-color:#43647d}.dark .lp-feedback{color:#a0e4c9}.dark .lp-hints p{background:#243e54}.dark .studio-result{background:#23415e}.dark .linear-studio th{background:#243e54}.dark .named-project.algebra-boot-camp{background:#32282b}.dark .named-project.salary-project{background:#21392f}
@media(max-width:700px){.linear-pathway .inline-notes:has(.note-preview){grid-template-columns:85px minmax(0,1fr);gap:13px;padding:18px}.project-brand-heading{min-height:85px}.project-brand-heading img{max-height:80px}.linear-practice{padding:20px 16px}.lp-fields label{min-width:110px}.linear-studio{padding:17px}.studio-controls{gap:14px}.linear-challenge{padding:22px}.studio-drawing svg text{font-size:13px}}
@media(max-width:420px){.linear-pathway .inline-notes:has(.note-preview){grid-template-columns:1fr}.note-preview{width:100px;float:left}.lp-fields{display:grid;grid-template-columns:1fr}.studio-controls{grid-template-columns:1fr}.bootcamp-days article{gap:12px}.bootcamp-days h2{font-size:22px}}
/* Project artwork fits its own proportions without a separate white frame. */
.named-project .project-brand-heading{height:76px;min-height:76px;padding:0;background:transparent;border:0;border-radius:0}
.project-brand-heading img{max-height:68px;width:100%;height:auto;mix-blend-mode:multiply}
.named-project>p{min-height:44px;display:flex;align-items:center;justify-content:center;margin:10px 0}
.project-guide-brand{background:transparent;padding:0;mix-blend-mode:multiply}
.dark .project-brand-heading{background:white;border-radius:7px;padding:6px}
.dark .project-brand-heading img,.dark .project-guide-brand{mix-blend-mode:normal}
.dark .project-guide-brand{background:white;border-radius:8px;padding:10px}
.studio-table-wrap{max-height:420px;overflow:auto}
@media(max-width:700px){.named-project .project-brand-heading{height:84px;min-height:84px}.project-brand-heading img{max-height:76px}.named-project>p{min-height:0}.lp-content h3{overflow-wrap:anywhere}}
.proficiency-details{margin-top:10px;border-top:1px solid #d4e0ec;padding-top:6px;text-align:left}
.proficiency-details>summary{min-height:44px;cursor:pointer;font-size:13px;font-weight:700;padding:12px 4px;text-align:center;list-style-position:inside;color:#285471}
.proficiency-details>p{font-size:13px;line-height:1.75;text-align:center;margin:12px 0}
.proficiency-levels{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:16px}
.proficiency-levels section{padding:18px;background:var(--paper);border:1px solid #d6e3ef;border-radius:9px}
.proficiency-levels h3{font-size:17px;color:#1354a0}.proficiency-levels ul{padding-left:18px;margin-bottom:0}.proficiency-levels li{font-size:13px;line-height:1.75;margin-bottom:9px}
.dark .proficiency-details>summary,.dark .proficiency-levels h3{color:#c4dfff}
@media(max-width:600px){.proficiency-levels{grid-template-columns:1fr}}
/* Math home: photographic welcome, visual unit directory and immediate lesson access. */
.math-home-hero{position:relative;isolation:isolate;overflow:hidden;border-radius:20px;color:#fff;background:#12344b;min-height:365px;padding:28px 38px 36px}.math-home-hero>img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;object-position:center 56%;z-index:-2}.math-home-hero:after{content:'';position:absolute;inset:0;background:linear-gradient(90deg,#051c32e8 0%,#092b42b5 52%,#092b4220 100%);z-index:-1}.math-home-hero .breadcrumb{color:#e7f1ff;font-size:12px;margin-bottom:28px}.math-home-label{font-size:11px;font-weight:700;letter-spacing:2px;color:#d0e4ff;margin:0 0 13px}.math-home-hero h1{font-size:clamp(32px,3.5vw,48px);max-width:680px;line-height:1.12;letter-spacing:-.045em}.math-home-intro{font-size:15px;line-height:1.75;max-width:510px;margin:18px 0 22px}.math-home-search{display:flex;align-items:center;gap:12px;background:#fff;border:1px solid #ffffff90;border-radius:35px;padding:6px 6px 6px 18px;color:#163652;max-width:520px;box-shadow:0 5px 25px #00172d22}.math-home-search input{min-width:0;flex:1;border:0;background:transparent;color:#163652;height:40px;font-size:13px}.math-home-search input::placeholder{color:#586c85;opacity:1}.math-home-search .primary{border-radius:25px;padding:10px 19px;font-size:12px;min-height:42px}.math-home-jumps{display:flex;justify-content:center;gap:25px;border-bottom:1px solid var(--line);padding:12px 8px}.math-home-jumps a{font-size:12px;font-weight:700;min-height:44px;display:flex;align-items:center;color:var(--blue)}.math-home-rail .math-textbook{display:flex;gap:8px;align-items:center;margin:20px 7px;font-size:12px;font-weight:700;min-height:44px;line-height:1.6}.math-skill-help{display:grid;grid-template-columns:1fr 1.7fr;gap:26px;padding:28px;background:linear-gradient(120deg,#edf5ff,#f0edfc);border-radius:16px;margin:28px 0;color:#173451}.math-skill-help h2{font-size:23px;line-height:1.3}.math-skill-help p:last-child{font-size:12px;color:#536481;margin-bottom:0}.math-skill-help .section-kicker{color:#4f6387;font-size:10px;margin:0 0 8px}.math-skill-help nav{display:grid;grid-template-columns:1fr 1fr;gap:8px 18px;align-content:center}.math-skill-help nav a{font-size:12px;font-weight:700;display:flex;gap:12px;justify-content:space-between;align-items:center;min-height:44px;padding:8px 0;border-bottom:1px solid #ccd9ed}.math-skill-help nav a span{color:#1464ed}.math-section-heading{display:flex;justify-content:space-between;align-items:end;gap:26px;margin:35px 0 21px}.math-section-heading h2{font-size:27px;line-height:1.25}.math-section-heading .section-kicker{margin:0 0 10px;font-size:10px;color:var(--muted)}.math-section-heading>p{font-size:12px;color:var(--muted);margin:0;line-height:1.7}.math-section-heading>a{color:var(--blue);font-size:12px;font-weight:700;min-height:44px;display:flex;align-items:center;flex-shrink:0}.math-catalog,.math-projects,.math-skill-help{scroll-margin-top:100px}.math-catalog-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px}.math-unit-preview{--sketch:#1764c5;--tint:#edf5ff;background:var(--paper);border:1px solid var(--line);border-radius:16px;overflow:hidden;box-shadow:0 4px 17px #203c6408;display:flex;flex-direction:column;transition:box-shadow .18s,border-color .18s}.math-unit-preview:hover{border-color:#a4bee1;box-shadow:0 9px 25px #203c6414}.math-unit-preview.mark-teal{--sketch:#007c72;--tint:#eaf7f3}.math-unit-preview.mark-coral{--sketch:#bd3e50;--tint:#fff0ef}.math-unit-preview.mark-amber{--sketch:#9b6105;--tint:#fff6df}.math-unit-preview.mark-violet{--sketch:#7643ba;--tint:#f3effc}.math-unit-main{display:block;padding:0 23px 20px;flex:1}.math-preview-art{margin:0 -23px 22px;height:112px;display:flex;justify-content:center;background:var(--tint);border-bottom:1px solid #1734510a;padding:7px 20px}.math-preview-art svg{display:block;width:100%;max-width:300px;overflow:visible;fill:none;stroke:var(--sketch);stroke-width:1.6}.math-preview-art text{font:12px 'DM Sans',Arial,sans-serif;fill:var(--sketch);stroke:none;text-anchor:middle}.math-preview-art .sketch-large{font-size:29px;font-weight:700}.math-preview-art .sketch-fill{fill:var(--sketch);fill-opacity:.35}.math-preview-art .sketch-accent{stroke-width:3}.math-preview-art .sketch-dot{fill:var(--sketch)}.math-preview-art .sketch-grid{opacity:.2;stroke-width:1}.math-unit-heading{position:relative;padding-right:26px}.math-category{font-size:9px;text-transform:uppercase;letter-spacing:1.3px;color:var(--sketch);font-weight:700;display:block;margin-bottom:8px}.math-unit-heading h3{font-size:23px;line-height:1.25}.math-unit-arrow{position:absolute;right:0;bottom:0;font-size:24px;font-weight:400;color:var(--sketch)}.math-unit-main>p{font-size:13px;line-height:1.8;margin:12px 0 14px;color:var(--muted)}.math-open-unit{font-size:12px;font-weight:700;color:var(--blue)}.math-lesson-shortcuts{display:flex;flex-wrap:wrap;justify-content:center;padding:9px 15px;border-top:1px solid var(--line);gap:0 15px;background:var(--bg)}.math-lesson-shortcuts a{font-size:11px;line-height:1.5;min-height:44px;display:inline-flex;align-items:center;text-align:center;color:var(--ink);text-decoration:underline;text-decoration-color:#adbed2;text-underline-offset:4px}.math-activity{background:#12354c;color:white;border-radius:16px;overflow:hidden;display:flex;flex-direction:column}.math-activity>img{width:100%;height:112px;object-fit:cover;object-position:center 50%;opacity:.9}.math-activity>div{padding:25px}.math-activity .section-kicker{color:#c8e3f4;font-size:10px;margin:0 0 12px}.math-activity h3{font-size:24px}.math-activity p:not(.section-kicker){font-size:13px;line-height:1.8;color:#e0ebf7}.math-activity a{font-size:12px;font-weight:700;min-height:44px;display:inline-flex;align-items:center;color:#fff}.math-project-pair{display:grid;grid-template-columns:1fr 1fr;gap:22px}.math-project-feature{border:1px solid var(--line);border-radius:16px;background:linear-gradient(135deg,var(--paper),var(--soft));overflow:hidden;display:flex;flex-direction:column;text-align:center}.math-project-feature>a{padding:20px 25px;flex:1;display:flex;flex-direction:column;align-items:center}.math-project-logo{height:96px;width:100%;display:flex;align-items:center;justify-content:center}.math-project-logo img{width:auto;height:auto;max-width:100%;max-height:78px;mix-blend-mode:multiply;object-fit:contain}.math-project-feature p{font-size:13px;line-height:1.8;color:var(--muted);margin:14px 0 17px}.math-project-feature .math-open-unit{margin-top:auto;min-height:32px;display:flex;align-items:center}.math-project-feature nav{border-top:1px solid var(--line);padding:10px 18px;display:flex;justify-content:center;flex-wrap:wrap;gap:4px 20px}.math-project-feature nav a{font-size:11px;font-weight:600;display:flex;align-items:center;min-height:44px;color:var(--blue)}.math-classroom{display:flex;gap:20px;align-items:start;border-top:1px solid var(--line);margin-top:40px;padding:32px 0}.math-classroom-icon{padding:12px;border-radius:13px;background:var(--soft);color:var(--blue)}.math-classroom>div:nth-child(2){flex:1}.math-classroom h2{font-size:21px}.math-classroom p{font-size:12px;line-height:1.8;max-width:650px;margin:10px 0}.math-classroom>a{font-size:12px;font-weight:700;color:var(--blue);white-space:nowrap;min-height:44px;display:flex;align-items:center}.math-home .advertising-break{margin:30px 0}.dark .math-skill-help{background:linear-gradient(120deg,#17334b,#2a2948);color:#e7efff}.dark .math-skill-help p,.dark .math-skill-help .section-kicker{color:#bbcce2}.dark .math-skill-help nav a{border-color:#536481}.dark .math-unit-preview{--tint:#142d48;--sketch:#90b9fa}.dark .math-unit-preview.mark-teal{--tint:#123d37;--sketch:#7ad8c9}.dark .math-unit-preview.mark-coral{--tint:#412734;--sketch:#ffb4bf}.dark .math-unit-preview.mark-amber{--tint:#3e3422;--sketch:#f8d27b}.dark .math-unit-preview.mark-violet{--tint:#30264c;--sketch:#c7acff}.dark .math-project-logo{background:#fff;border-radius:8px;padding:8px}.dark .math-project-logo img{mix-blend-mode:normal}.dark .math-home-jumps a,.dark .math-open-unit,.dark .math-classroom>a,.dark .math-project-feature nav a,.dark .math-section-heading>a{color:#94bdff}
@media(min-width:1500px){.math-home-hero{min-height:390px;padding:32px 42px 40px}.math-home-hero h1{font-size:50px}}
@media(max-width:1000px){.math-home{display:block}.math-home-rail{display:none}.math-home-hero h1{font-size:43px}}
@media(max-width:760px){.math-home-hero{padding:23px 23px 28px;min-height:390px;border-radius:16px}.math-home-hero .breadcrumb{margin-bottom:28px}.math-home-hero h1{font-size:35px}.math-home-hero:after{background:linear-gradient(90deg,#051c32ed,#092b4285)}.math-home-intro{font-size:14px;line-height:1.8}.math-home-search{gap:8px;padding-left:12px}.math-home-search input{font-size:12px}.math-home-search .primary{padding:10px 13px}.math-home-search>.icon{width:17px;flex-shrink:0}.math-home-jumps{gap:5px 18px;flex-wrap:wrap;justify-content:flex-start;padding:8px 2px}.math-home-jumps a{font-size:11px}.math-skill-help{grid-template-columns:1fr;padding:23px;gap:13px;margin:23px 0}.math-skill-help h2{font-size:24px}.math-skill-help nav{gap:4px 18px}.math-skill-help nav a{font-size:12px}.math-section-heading{display:block;margin:30px 0 18px}.math-section-heading h2{font-size:26px}.math-section-heading>p{margin:12px 0 0}.math-section-heading>p br{display:none}.math-catalog-grid{gap:18px}.math-unit-main{padding:0 18px 18px}.math-preview-art{margin-left:-18px;margin-right:-18px;padding-left:8px;padding-right:8px}.math-unit-heading h3{font-size:21px}.math-unit-main>p{font-size:13px}.math-project-pair{gap:18px}.math-project-feature>a{padding:18px}.math-project-logo{height:84px}.math-classroom{flex-wrap:wrap;gap:14px}.math-classroom>div:nth-child(2){flex-basis:calc(100% - 65px)}.math-classroom>a{margin-left:59px}.math-home .advertising-break{margin:24px 0}}
@media(max-width:560px){.math-catalog-grid,.math-project-pair{grid-template-columns:1fr}.math-unit-preview{border-radius:14px}.math-preview-art{height:106px}.math-unit-main{padding:0 22px 20px}.math-preview-art{margin-left:-22px;margin-right:-22px;margin-bottom:20px}.math-unit-heading h3{font-size:24px}.math-unit-main>p{font-size:14px}.math-lesson-shortcuts a{font-size:12px}.math-activity>img{height:145px}.math-project-logo{height:95px}.math-project-feature>a{padding:22px}.math-project-feature p{font-size:14px}.math-project-feature nav a{font-size:12px}.math-home-jumps{gap:0 18px}.math-home-hero h1{font-size:33px}}
@media(prefers-reduced-motion:reduce){.math-unit-preview{transition:none}}
.math-home-search .sr-label{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.math-unit-main{display:flex;flex-direction:column}.math-unit-main>.math-open-unit{margin-top:auto}.math-preview-art{flex-shrink:0}.math-unit-main>p{flex:1}
@media(max-width:560px){.math-project-logo{height:78px}.math-project-logo img{max-height:66px}}
/* Subject hub: compact orientation, with the unit directory immediately below. */
.math-home-hero.math-hub-header{display:grid;grid-template-columns:minmax(0,1fr) minmax(250px,315px);align-items:center;gap:30px;min-height:208px;padding:25px 30px}.math-hub-header .breadcrumb{margin:0 0 18px;font-size:11px}.math-home-hero.math-hub-header h1{font-size:42px;line-height:1.1}.math-hub-header .math-home-intro{font-size:14px;line-height:1.7;max-width:460px;margin:12px 0 0}.math-hub-header .math-home-search{width:100%;margin-top:22px;gap:8px;padding-left:13px}.math-hub-header .math-home-search input{font-size:12px}.math-hub-header .math-home-search .primary{padding:10px 14px}.math-hub-header .math-home-search>.icon{flex-shrink:0;width:18px}.math-home .math-catalog>.math-section-heading{margin-top:25px}.math-home .math-catalog>.math-section-heading .section-kicker{display:none}.math-home .math-home-jumps{padding-top:5px;padding-bottom:5px}.math-catalog-grid>.advertising-break{grid-column:1/-1;margin:4px 0}.math-home .math-skill-help{margin-top:28px}.math-home-hero.math-hub-header:after{background:linear-gradient(90deg,#051c32e8,#092b4280)}
@media(max-width:1100px){.math-home-hero.math-hub-header{grid-template-columns:minmax(0,1fr) minmax(230px,285px);gap:22px;padding:24px}.math-hub-header .math-home-intro{font-size:13px}}
@media(max-width:760px){.math-home-hero.math-hub-header{grid-template-columns:1fr;gap:17px;min-height:0;padding:22px}.math-home-hero.math-hub-header h1{font-size:35px}.math-hub-header .breadcrumb{margin-bottom:15px}.math-hub-header .math-home-intro{font-size:14px;max-width:460px;margin-top:10px}.math-hub-header .math-home-search{margin-top:0;max-width:440px}.math-home .math-catalog>.math-section-heading{margin-top:22px}.math-home .math-home-jumps{gap:0 17px;padding:4px 0}.math-home .math-home-jumps a{font-size:11px}.math-catalog-grid>.advertising-break{margin:0}}
.math-hub-heading,.math-hub-header .math-home-search{min-width:0}
@media(max-width:760px){.math-home-hero.math-hub-header{grid-template-columns:minmax(0,1fr)}}
/* Fractions: exact equal-whole models and source-led teaching within the shared unit design. */
.fraction-pathway .immersive-heading h1{font-size:clamp(30px,3.2vw,45px);line-height:1.2}.fraction-pathway .immersive-heading{background-position:center 44%}.fraction-pathway .reference-content{min-width:0}.fraction-model{border:1px solid #c4dce5;border-radius:13px;background:#fff;color:#193b54;padding:20px;margin:20px 0 7px}.fm-controls{display:flex;flex-wrap:wrap;gap:15px;align-items:end}.fm-controls fieldset{border:1px solid #c4d6e4;border-radius:10px;display:flex;gap:12px;min-width:0;flex:1;padding:12px}.fm-controls legend{font-size:12px;font-weight:700;padding:0 5px}.fm-controls label{display:grid;gap:6px;font-size:12px;font-weight:600;min-width:0;flex:1}.fm-controls>label{flex-basis:180px;max-width:100%}.fm-controls input,.fm-controls select{background:#fff;border:1px solid #9fb9cd;border-radius:8px;color:#193b54;min-height:44px;width:100%;min-width:0;padding:8px;font:inherit;font-size:14px}.fm-drawing svg{width:100%;height:auto;display:block;margin:19px 0 8px;border-radius:9px;background:#f6fafc}.fm-result{background:#e7f4f1;border-left:3px solid #16786a;border-radius:0 8px 8px 0;padding:15px;font-size:14px!important;line-height:1.8!important;color:#234a45}.fraction-model .quiet-caption{font-size:11px;line-height:1.8;color:#52677c}.fraction-table-wrap{overflow:auto;margin-top:20px}.fraction-table-wrap table{border-collapse:collapse;width:100%;font-size:13px;text-align:left}.fraction-table-wrap caption{font-weight:700;text-align:left;margin-bottom:12px}.fraction-table-wrap th,.fraction-table-wrap td{padding:13px 10px;border:1px solid #b9cddc;line-height:1.7}.fraction-table-wrap th{background:#edf5fb}.fraction-notes-section{scroll-margin-top:100px}.fraction-inline-notes{margin:25px 0 10px}.fraction-note-thumbnail{display:block;width:100%;max-height:220px;overflow:hidden;border:1px solid #e2cfad;border-radius:9px;background:white;margin:16px 0}.fraction-note-thumbnail img{display:block;width:100%;height:auto;object-fit:cover;object-position:top}.fraction-pathway .optics-prose h2{font-size:25px;line-height:1.3}.fraction-pathway .fraction-explanation h2:not(:first-child){margin-top:32px}.fraction-media-invite{display:flex;align-items:start;gap:18px;padding:25px;background:#edf4fb;border:1px solid #c5d8e8;border-radius:12px;margin:20px 0;color:#23435c}.fraction-media-invite>img{width:46px;height:36px;object-fit:contain;flex-shrink:0}.fraction-media-invite h3{font-size:20px;line-height:1.4;margin:8px 0}.fraction-media-invite p{font-size:13px;line-height:1.8;margin:10px 0}.fraction-media-invite a{font-size:12px;font-weight:700;min-height:44px;display:inline-flex;align-items:center;color:#075eb8;text-decoration:underline;text-underline-offset:3px}.fraction-video-thumb{width:100%;height:100%;position:absolute;inset:0;object-fit:cover;opacity:.35}.fraction-pathway .media-stage>button,.fraction-pathway .media-stage>span{position:relative;z-index:1}.fraction-pathway .media-stage>button{margin:15px;font-size:12px}.fraction-pathway .media-stage>span{margin-bottom:20px}.fraction-connection{margin:24px 0;padding:26px;border-radius:12px;background:linear-gradient(120deg,#eaf6f2,#f0f5ff);color:#214c47}.fraction-connection h2{font-size:22px;margin:10px 0}.fraction-connection p{font-size:14px;line-height:1.9;margin:10px 0 0}.fraction-side-connection{margin-top:24px;border-top:1px solid var(--line);padding-top:22px}.fraction-side-connection img{width:100%;height:130px;object-fit:cover;border-radius:10px;margin-bottom:15px}.fraction-side-connection p{font-size:12px;line-height:1.8;color:var(--muted)}.fraction-side-connection a{font-size:12px;font-weight:700;color:var(--blue);min-height:44px;display:flex;align-items:center}.fraction-operation-map{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:24px 0 4px}.fraction-operation-map a{display:grid;grid-template-columns:32px 1fr;gap:5px 12px;background:#fff;border:1px solid #e0d8f2;padding:16px;border-radius:10px;color:#383153}.fraction-operation-map a>span{grid-row:span 2;font-size:28px;font-weight:500;color:#7445b7}.fraction-operation-map strong{font-size:13px;line-height:1.5}.fraction-operation-map small{font-size:12px;color:#625a79}.fraction-activities{padding:32px 0;scroll-margin-top:100px}.fraction-activities>h2{margin:10px 0 22px;font-size:26px}.fraction-activity-pair{display:grid;grid-template-columns:1fr 1fr;gap:17px}.fraction-activity-pair article{border-radius:14px;padding:25px 20px;background:linear-gradient(145deg,#e9f4ef,#f6fbf8);border:1px solid #bcd8cc;text-align:center;color:#244a40;scroll-margin-top:110px}.fraction-activity-pair article:nth-child(2){background:linear-gradient(145deg,#f2edfb,#faf8ff);border-color:#d1c1e6;color:#4e386d}.fraction-activity-mark{display:block;font:700 22px/1.6 Manrope,Arial,sans-serif;letter-spacing:.03em;margin:8px 0 17px}.fraction-activity-pair h3{font-size:23px;line-height:1.4}.fraction-activity-pair p{font-size:13px;line-height:1.8;margin:13px 0}.fraction-activity-pair a{display:flex;justify-content:center;align-items:center;min-height:44px;font-size:12px;font-weight:700;text-decoration:underline;text-underline-offset:4px}.fraction-resource-group{margin-top:17px;border-top:1px solid #b6c9d9;padding-top:8px}.fraction-resource-group summary{font-size:14px;font-weight:700;min-height:44px;padding:10px;cursor:pointer;text-align:center}.fraction-role-list{display:grid;grid-template-columns:repeat(3,1fr);gap:15px;margin:25px 0}.fraction-role-list article{padding:20px 15px;border:1px solid var(--line);border-radius:12px;background:var(--soft)}.fraction-role-list b{display:inline-grid;place-items:center;width:31px;height:31px;border-radius:50%;background:var(--blue);color:white;margin-bottom:14px}.fraction-role-list h3{font-size:18px}.fraction-role-list p{font-size:13px!important;line-height:1.75!important;margin-bottom:0}.fraction-card-types{display:grid;gap:18px;margin-top:24px}.fraction-card-types>div{padding:20px;border:1px solid var(--line);background:var(--paper);border-radius:10px}.fraction-card-types dt{font-size:18px;font-weight:700;margin-bottom:8px}.fraction-card-types dd{font-size:14px;line-height:1.8;margin:0}.fraction-pathway .linear-practice h3{font-size:21px;line-height:1.55;letter-spacing:-.02em}.fraction-pathway .lp-fields input{min-width:0;max-width:100%}.fraction-pathway .optics-trap summary{cursor:pointer;min-height:44px;padding:10px 0;font-weight:700}.dark .fraction-media-invite{background:#20344c;border-color:#526d89;color:#e3edf9}.dark .fraction-media-invite a,.dark .fraction-side-connection a{color:#a9d0ff}.dark .fraction-connection{background:linear-gradient(120deg,#153e34,#233f59);color:#e2f2ed}.dark .fraction-operation-map a{background:#26334d;border-color:#596386;color:#e7e9fb}.dark .fraction-operation-map small{color:#c3cde0}.dark .fraction-activity-pair article{background:#1a392f;border-color:#4b7864;color:#d8eee3}.dark .fraction-activity-pair article:nth-child(2){background:#342447;border-color:#7b5c99;color:#e6d8fa}
@media(max-width:760px){.fraction-pathway .immersive-heading{padding:25px 22px 36px;min-height:230px}.fraction-pathway .immersive-heading h1{font-size:32px}.fraction-model{padding:15px 12px}.fm-controls{gap:12px}.fm-controls fieldset{flex-basis:100%;padding:10px}.fm-controls label{font-size:12px}.fm-drawing svg{margin-top:17px}.fraction-operation-map{grid-template-columns:1fr}.fraction-note-thumbnail{max-height:190px}.fraction-inline-notes{grid-template-columns:1fr;padding:20px}.fraction-inline-notes>.note-icon{display:none}.fraction-media-invite{padding:20px 17px;gap:13px}.fraction-media-invite>img{width:35px}.fraction-activity-pair,.fraction-role-list{grid-template-columns:1fr}.fraction-pathway .reference-block{padding:22px 18px}.fraction-pathway .optics-prose h2{font-size:24px}.fraction-pathway .linear-practice{padding:20px 16px}.fraction-pathway .linear-practice h3{font-size:19px}.fraction-pathway .lp-actions{gap:9px}.fraction-pathway .optics-question label{padding:12px 10px}.fraction-table-wrap th,.fraction-table-wrap td{padding:10px 7px;font-size:12px}}
.fm-native-bars{display:none}.fm-diagram-label{font-size:14px;font-weight:700;line-height:1.7;margin:20px 0 4px}.fm-order-steps{list-style:none;padding:0;margin:24px 0}.fm-order-steps li{padding:16px;background:#edf4fa;border:1px solid #c4d6e4;border-radius:8px;margin:10px 0;font-size:20px;line-height:1.7;overflow-wrap:anywhere}
@media(max-width:760px){.fraction-pathway #model.reference-block{padding:22px 12px}.fraction-model{padding:15px 9px}.fm-bar-svg{display:none!important}.fm-native-bars{display:grid;gap:21px;margin:23px 0 16px}.fm-native-bars h4{font:700 13px/1.7 'DM Sans',Arial,sans-serif;letter-spacing:0;margin-bottom:9px}.fm-native-whole{display:grid;height:32px;border:1px solid #366c70;margin:7px 0;background:white}.fm-native-whole span{border-right:1px solid #789c9e}.fm-native-whole span:last-child{border:0}.fm-native-whole .filled{background:#94cfc4}.fm-native-bars section:nth-child(2) .filled{background:#c8b6e8}.fm-diagram-label{font-size:13px}.fm-order-steps li{font-size:17px;padding:13px}.fraction-pathway .fm-drawing svg{margin-top:12px}}
.fraction-activity-art{display:block;width:100%;height:110px;object-fit:cover;object-position:center;border-radius:9px;margin:3px 0 20px}.fraction-activity-mark{min-height:110px;display:flex;align-items:center;justify-content:center;border:1px dashed #b99ed8;border-radius:9px;background:#ffffff80;margin:3px 0 20px;font-size:18px}.fraction-guide-cover{display:block;width:100%;height:auto;border-radius:13px;margin:0 0 28px}
.dark .fraction-pathway .optics-practice{background:#14382f;color:#e2f4ec}.dark .fraction-pathway .linear-practice{color:#e7f1ff}.dark .fraction-pathway .linear-vocabulary dt{color:#bdd9ff}.dark .fraction-pathway .learning-collection{color:#e5eef9}.dark .fraction-pathway .learning-collection p{color:#c1d2e3}.dark .fraction-pathway .learning-collection a{color:#bddbff}.dark .fraction-pathway .learning-collection h3{color:#edf5ff}
.dark .fraction-pathway .entry-notes a,.dark .fraction-pathway .hub-jumps a,.dark .fraction-pathway .text-link,.dark .fraction-pathway .learning-tabs a{color:#bddbff}.dark .fraction-pathway .unit-indicators .section-kicker{color:#c0d2e6}
/* Fractions refinement: a clear unit map and quieter, contextual lesson materials. */
.fraction-hub .unit-entry{padding:22px 6px 12px}.fraction-hub .unit-indicators{padding:15px 18px}.fraction-hub .proficiency-details{background:transparent;border:0;border-top:1px solid #cbdde9;border-radius:0;padding:0;margin-top:4px}.fraction-hub .proficiency-details>summary{padding:10px 3px;min-height:44px}.fraction-hub .entry-notes{margin-top:20px}.fraction-hub .entry-notes h2{display:flex;align-items:center;justify-content:center;gap:9px;margin-bottom:9px}.fraction-hub .entry-notes a{font-size:13px;min-height:44px}.fraction-hub .entry-notes nav{gap:0 22px}.fraction-hub .unit-companion nav a{gap:11px;padding:12px 0!important}.fraction-hub .unit-companion nav .icon{width:18px;height:18px;color:var(--blue);flex-shrink:0}.fraction-hub .unit-companion nav strong{font-size:12px;font-weight:700;display:block}.fraction-hub .unit-companion nav small{font-size:11px;line-height:1.6;display:block;color:var(--muted);margin-top:3px}.fraction-hub .unit-companion .fraction-side-connection{background:transparent;box-shadow:none;border-radius:0;padding:20px 8px!important}
.fraction-lesson-directory{margin-top:26px}.fraction-lesson-chapter{padding:23px 0 12px;border-top:1px solid var(--line)}.fraction-lesson-chapter>header{display:flex;align-items:center;gap:14px}.fraction-chapter-mark{width:46px;height:46px;display:grid;place-items:center;border-radius:12px;background:#e5f1fb;color:#176295;font-size:22px;flex-shrink:0}.fraction-lesson-chapter:nth-child(2) .fraction-chapter-mark{background:#eee7fb;color:#7145b3}.fraction-lesson-chapter:nth-child(3) .fraction-chapter-mark{background:#e2f2eb;color:#207360}.fraction-pathway .fraction-lesson-chapter h3{font-size:19px;line-height:1.4;margin:0}.fraction-pathway .fraction-lesson-chapter header p{font-size:12px;line-height:1.7;margin:4px 0 0;color:var(--muted)}.fraction-lesson-directory .linear-lesson-list{margin-top:11px;gap:0 24px}.fraction-lesson-directory .linear-lesson-list>a{padding:15px 0;min-height:82px;gap:12px}.fraction-lesson-directory .linear-lesson-list>a>b{min-width:30px;width:30px;height:32px;border-radius:8px;font-size:11px;background:var(--soft);color:var(--muted)}.fraction-lesson-directory .linear-lesson-list strong{font-size:14px;line-height:1.55}.fraction-lesson-directory .linear-lesson-list .icon{width:17px;min-width:17px}.fraction-lesson-directory .linear-lesson-list>a:hover strong{text-decoration:underline;text-underline-offset:4px}.fraction-lesson-chapter:last-child .linear-lesson-list>a{border-bottom:0}
.fraction-inline-notes{grid-template-columns:132px minmax(0,1fr);gap:22px;padding:22px;margin:25px 0 16px;align-items:center;background:#fffaef;border-color:#e9dcc0}.fraction-inline-notes .fraction-note-thumbnail{width:132px;height:176px;max-height:none;margin:0;position:relative;border-radius:6px;box-shadow:0 5px 14px #66502312;align-self:start}.fraction-inline-notes .fraction-note-thumbnail img{width:100%;height:auto;min-height:100%;object-fit:cover}.fraction-note-thumbnail>span{position:absolute;bottom:0;left:0;right:0;display:block;text-align:center;font-size:11px;font-weight:700;padding:8px 4px;background:#fff8e8f5;border-top:1px solid #e6d7b7;color:#72450b}.fraction-note-copy .section-kicker{display:flex;align-items:center;gap:7px}.fraction-note-copy .section-kicker .icon{width:15px;height:15px}.fraction-inline-notes h3{font-size:21px;margin:9px 0}.fraction-inline-notes p{font-size:13px;line-height:1.8;margin:9px 0}.fraction-inline-notes .note-actions{gap:2px 18px}.fraction-inline-notes .pdf-slot{grid-column:1/-1;min-width:0}.fraction-inline-notes .pdf-slot object{margin-top:0}.fraction-pathway .learning-tabs a[aria-current=location]{background:#eaf2ff;box-shadow:inset 0 -2px #1464ed;color:#0757db}.fraction-pathway .learning-tabs a:hover{background:var(--soft)}
.dark .fraction-hub .proficiency-details{border-top-color:#486479}.dark .fraction-hub .unit-companion nav .icon{color:#bddbff}.dark .fraction-chapter-mark{background:#203d55;color:#bbddf8}.dark .fraction-lesson-chapter:nth-child(2) .fraction-chapter-mark{background:#37294e;color:#e2ccff}.dark .fraction-lesson-chapter:nth-child(3) .fraction-chapter-mark{background:#214b40;color:#c0eadc}.dark .fraction-inline-notes{background:#3e3526;border-color:#756548;color:#f3e9d8}.dark .fraction-note-copy .section-kicker,.dark .fraction-inline-notes .note-actions a,.dark .fraction-inline-notes .note-actions button{color:#f6d796}.dark .fraction-pathway .learning-tabs a[aria-current=location]{background:#203e61;color:#c3deff;box-shadow:inset 0 -2px #83b6ff}
@media(min-width:1100px){.fraction-lesson .learning-tabs{position:sticky;top:74px;z-index:5;background:var(--paper);margin-top:0}.fraction-lesson :is(#learn,#model,#examples,#guided,#practice,#notes){scroll-margin-top:150px}}
@media(max-width:760px){.fraction-hub .unit-entry{padding:19px 0 10px}.fraction-hub .unit-indicators{padding:14px 12px}.fraction-hub .entry-notes nav{gap:0 18px}.fraction-hub .entry-notes a{font-size:13px}.fraction-lesson-directory .linear-lesson-list{grid-template-columns:1fr}.fraction-lesson-directory .linear-lesson-list>a{min-height:64px;padding:13px 0}.fraction-lesson-directory .linear-lesson-list strong{font-size:15px}.fraction-pathway .fraction-lesson-chapter h3{font-size:19px}.fraction-lesson-chapter{padding-top:21px}.fraction-chapter-mark{width:40px;height:43px}.fraction-inline-notes{grid-template-columns:85px minmax(0,1fr);gap:14px;padding:17px 14px;align-items:start}.fraction-inline-notes .fraction-note-thumbnail{width:85px;height:117px}.fraction-inline-notes h3{font-size:18px;line-height:1.4;margin-top:8px}.fraction-inline-notes .fraction-note-copy p{font-size:13px}.fraction-note-thumbnail>span{font-size:10px;padding:6px 2px}.fraction-inline-notes .note-actions{grid-column:1/-1;gap:0 13px}.fraction-inline-notes .note-actions a,.fraction-inline-notes .note-actions button{font-size:12px;min-height:44px}.fraction-note-copy{display:contents}.fraction-note-copy .section-kicker{grid-column:2;align-self:end;margin-bottom:-10px}.fraction-note-copy h3{grid-column:2;grid-row:2;margin-top:0}.fraction-inline-notes .fraction-note-thumbnail{grid-row:1/4}.fraction-note-copy p{grid-column:1/-1;margin:0}.fraction-note-copy .note-actions{display:flex}.fraction-inline-notes .pdf-slot{grid-row:auto}.fraction-note-copy .section-kicker .icon{display:none}}

/* Give the lesson directory an unmistakable boundary within the unit hub. */
.unit-lesson-section{margin:24px 0;padding:25px 22px 22px;border:1px solid #b8cfe9;border-top:4px solid #2468ce;border-radius:15px;background:linear-gradient(140deg,#eaf3ff,#f3f7fd);box-shadow:0 5px 18px #183e7210}.unit-lesson-section>h2{color:#173d6b;margin-top:9px}.unit-lesson-section>.section-kicker{color:#285d96}.unit-lesson-section>p{font-size:14px;line-height:1.8;color:#3e5570}.fraction-hub .fraction-lesson-directory{margin-top:21px;display:grid;gap:15px}.fraction-hub .fraction-lesson-chapter{padding:20px 17px 6px;background:#fff;border:1px solid #d4e0ed;border-radius:11px}.fraction-hub .fraction-lesson-chapter .linear-lesson-list>a:last-child{border-bottom:0}.fraction-hub .fraction-lesson-chapter:last-child .linear-lesson-list>a{border-bottom:1px solid var(--line)}.fraction-hub .fraction-lesson-chapter:last-child .linear-lesson-list>a:last-child{border-bottom:0}.fraction-hub .fraction-lesson-directory .linear-lesson-list strong{font-size:14px}.fraction-hub .fraction-lesson-directory .linear-lesson-list>a{min-height:74px}
.dark .unit-lesson-section{background:linear-gradient(140deg,#1a304b,#182a40);border-color:#4e719b;border-top-color:#83b6ff;box-shadow:none}.dark .unit-lesson-section>h2{color:#e7f1ff}.dark .unit-lesson-section>.section-kicker{color:#bad8ff}.dark .unit-lesson-section>p{color:#c6d5e7}.dark .fraction-hub .fraction-lesson-chapter{background:#15253a;border-color:#435b77}
@media(max-width:760px){.unit-lesson-section{padding:21px 13px 14px;margin:20px 0}.unit-lesson-section>h2{font-size:25px}.fraction-hub .fraction-lesson-chapter{padding:17px 12px 3px}.fraction-hub .fraction-lesson-chapter>header{gap:10px;align-items:start}.fraction-hub .fraction-lesson-chapter h3{font-size:18px}.fraction-hub .fraction-lesson-directory .linear-lesson-list>a{min-height:66px;gap:9px}.fraction-hub .fraction-lesson-directory .linear-lesson-list strong{font-size:14px}.fraction-hub .fraction-lesson-chapter:last-child .linear-lesson-list>a{border-bottom:1px solid var(--line)}.fraction-hub .fraction-lesson-chapter:last-child .linear-lesson-list>a:last-child{border:0}}
@media(max-width:400px){.unit-lesson-section{padding-left:10px;padding-right:10px}.fraction-hub .fraction-lesson-directory .linear-lesson-list>a>b{display:none}.fraction-hub .fraction-lesson-chapter{padding-left:11px;padding-right:11px}.fraction-hub .fraction-chapter-mark{width:32px;height:36px;font-size:19px;flex-shrink:0}}

/* Shared lesson surface across Math and Science hubs. */
.reference-content .unit-lesson-section{padding:25px 22px 22px}.unit-lesson-section>.numbered-heading{margin-top:18px}.unit-lesson-section .linear-lesson-list,.unit-lesson-section .optics-directory,.unit-lesson-section.compact-paths>nav,.unit-lesson-section>.unit-ideas{background:var(--paper);border:1px solid #d4e0ed;border-radius:11px;padding:7px 17px;margin-top:21px}.unit-lesson-section .linear-lesson-list>a:last-child,.unit-lesson-section .optics-directory>a:last-child{border-bottom:0}.unit-lesson-section>.unit-ideas{padding:19px}.unit-lesson-section.compact-paths .section-top{gap:12px;flex-wrap:wrap}.unit-lesson-section.compact-paths .section-top h2{font-size:25px}.unit-lesson-section .section-top>a{color:var(--blue);font-size:12px;min-height:44px;display:inline-flex;align-items:center}.unit-lesson-section .numbered-heading h2{color:#173d6b}.unit-lesson-section .numbered-heading p{color:#3e5570}.unit-lesson-section .fraction-lesson-chapter .linear-lesson-list{padding:0;margin-top:11px;border:0;border-radius:0;background:transparent}.dark .unit-lesson-section .linear-lesson-list,.dark .unit-lesson-section .optics-directory,.dark .unit-lesson-section.compact-paths>nav,.dark .unit-lesson-section>.unit-ideas{border-color:#435b77}.dark .unit-lesson-section .numbered-heading h2{color:#e7f1ff}.dark .unit-lesson-section .numbered-heading p{color:#c6d5e7}
@media(max-width:760px){.reference-content .unit-lesson-section{padding:21px 13px 14px}.unit-lesson-section .linear-lesson-list,.unit-lesson-section .optics-directory,.unit-lesson-section.compact-paths>nav{padding:5px 11px}.unit-lesson-section>.unit-ideas{padding:14px}.unit-lesson-section.compact-paths>nav{grid-template-columns:1fr}.unit-lesson-section .optics-directory>a{gap:10px}.unit-lesson-section .optics-directory>a>b{min-width:28px;width:28px}.unit-lesson-section .fraction-lesson-chapter .linear-lesson-list{padding:0}}
@media(max-width:400px){.reference-content .unit-lesson-section{padding-left:10px;padding-right:10px}.unit-lesson-section .linear-lesson-list>a>b,.unit-lesson-section .optics-directory>a>b,.unit-lesson-section.compact-paths>nav>a>b{display:none}}
/* Consistent reading rails: subject navigation left, in-page guidance right. */
@media(min-width:1101px){.reference-unit>.shared-unit-rail{align-self:stretch;position:relative;padding-top:8px;min-height:0}.unit-rail-sticky{position:sticky;top:94px;max-height:calc(100dvh - 110px);overflow-y:auto;overscroll-behavior:contain;scrollbar-width:thin;padding:0 2px 4px}.unit-rail-sticky .unit-back{margin:0 0 22px;padding-left:9px}.unit-rail-sticky .eyebrow{margin:0 0 14px;padding-left:9px}.unit-rail-sticky nav{gap:4px}.unit-rail-sticky nav a{min-height:50px;font-size:12px}.unit-rail-sticky .rail-photo{height:clamp(90px,calc(100dvh - 690px),180px);margin:22px 0 0}.unit-rail-sticky .rail-photo:after{display:none}.unit-companion{align-self:stretch}.unit-companion>.reading-guide{position:sticky;top:94px;max-height:calc(100dvh - 110px);overflow-y:auto;scrollbar-width:thin;margin-top:25px;padding:19px 16px;background:var(--paper);border:1px solid #c7d9ed;border-top:3px solid #4784d5;border-radius:12px;box-shadow:0 4px 16px #20457408}.reading-guide .section-kicker{font-size:9px;color:#416b96}.unit-companion .reading-guide h2{font-size:17px;margin:7px 0 12px}.unit-companion .reading-guide nav{display:grid;gap:0}.unit-companion .reading-guide nav a{min-height:39px;font-size:12px;display:flex;justify-content:space-between;gap:10px;padding:8px 0!important;border-bottom:1px solid var(--line);color:var(--muted)}.unit-companion .reading-guide nav a span{font-size:13px}.unit-companion .reading-guide nav a[aria-current=location]{color:var(--blue);font-weight:700}.unit-companion .reading-guide nav a:last-child{border:0}.reading-unit-link{display:flex;align-items:center;min-height:44px;font-size:11px;font-weight:700;color:var(--blue);margin-top:10px;border-top:1px solid var(--line)}.companion-lesson-picker .optics-picker{display:grid;gap:7px;font-size:11px;line-height:1.7}.companion-lesson-picker select{width:100%;min-width:0;min-height:44px;background:var(--paper);color:var(--ink);border:1px solid var(--line);padding:8px;border-radius:8px;font:inherit}.dark .unit-companion>.reading-guide{border-color:#44688c;border-top-color:#83b6ff}.dark .reading-guide .section-kicker{color:#bbd6f2}.dark .reading-unit-link,.dark .unit-companion .reading-guide nav a[aria-current=location]{color:#bddbff}}
@media(max-width:1100px){.reference-unit{display:block}.reference-unit>.shared-unit-rail{display:none}.unit-companion .reading-guide{display:none}}
/* Family identity: upright grade marker, independent main-site destination. */
.brand-family{display:flex;align-items:center;gap:14px;flex-shrink:0}.brand-family .brand{white-space:nowrap}.grade-navigation{display:flex;align-items:center;gap:3px;border-left:1px solid var(--line,#dce4ed);padding-left:10px}.grade-navigation a{display:flex;align-items:center;justify-content:center;gap:5px;min-width:30px;min-height:40px;padding:0 6px;font-size:13px;font-weight:750;text-decoration:none;color:var(--muted,#52647c);border-radius:7px}.grade-navigation .grade-current{color:#fff;background:#175fca;padding:0 9px;font-size:17px}.grade-current span{font-size:9px;letter-spacing:1px}.grade-navigation a:hover{outline:2px solid #64a1f3;outline-offset:2px}@media(max-width:600px){.brand-family{gap:8px}.brand-family .brand{font-size:15px}.grade-navigation{padding-left:7px}.grade-navigation a{min-width:25px;padding:0 4px}.grade-navigation .grade-current{padding:0 6px}.grade-current span{display:none}}
.rates-model svg{display:block;width:100%;height:auto;max-height:340px}.rates-model .rm-controls{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.rm-controls label{display:grid;gap:8px;font-weight:650}.rm-controls input{width:100%;min-width:0;padding:10px;border:1px solid #a7bdd7;border-radius:8px;background:var(--card,#fff);color:inherit}.rm-result{font-size:1.05rem;font-weight:650}.rates-project{background:linear-gradient(130deg,#103867,#225b88);color:white;border-radius:18px;padding:32px;text-align:center;margin:28px 0}.rates-project h2{color:white;font-size:clamp(36px,6vw,62px);margin:0}.rates-project p{max-width:52ch;margin:16px auto}.rates-project a{color:white;display:inline-block;margin:8px;padding:10px 16px;border:1px solid #a2c6e4;border-radius:8px}.rates-model table{width:100%;border-collapse:collapse}.rates-model td,.rates-model th{padding:9px;text-align:left;border-bottom:1px solid #a7bdd7}.rates-resources nav{display:flex;justify-content:center;flex-wrap:wrap;gap:12px}.rates-resources a{padding:10px}.rates-proportion-image{width:100%;border-radius:14px;margin:18px 0}.rates-model .rm-drawing{margin-top:22px}.rates-model{overflow:hidden}.rates-steps{counter-reset:steps}.rates-steps article{padding:22px 0;border-bottom:1px solid var(--line,#dce4ed)}@media(max-width:600px){.rates-model .rm-controls{grid-template-columns:1fr}.rates-project{padding:24px 18px}}
.rates-pathway .media-stage{position:relative;overflow:hidden;border-radius:12px;background:#14334f}.rates-pathway .media-stage>img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;opacity:.35}.rates-pathway .media-stage>button,.rates-pathway .media-stage>span{position:relative;z-index:1}.rates-pathway .media-stage.loaded iframe{position:absolute;inset:0;width:100%;height:100%;border:0}.rates-pathway .proficiency-details img{background:white}.rates-pathway .hub-jumps{scroll-margin-top:90px}
.rates-model input{background:var(--paper);color:var(--ink)}.rates-project .section-kicker{color:#c4ddf7}.grade-navigation a{color:var(--muted)}
/* Rates pathway: compact rows, aligned actions and calm resource groups. */
.rates-pathway .unit-lesson-section{padding:26px 22px;background:var(--soft);border-color:var(--line)}
.rates-pathway .fraction-lesson-directory{display:grid;gap:16px;margin-top:22px}
.rates-pathway .fraction-lesson-chapter{padding:19px 18px 8px;background:var(--paper);border:1px solid var(--line);border-radius:12px}
.rates-pathway .fraction-lesson-chapter>header{gap:12px;align-items:center;margin-bottom:12px}
.rates-pathway .fraction-lesson-chapter header p{font-size:13px;line-height:1.5;margin:5px 0 0}
.rates-pathway .fraction-chapter-mark{width:40px;height:40px;flex:0 0 40px;border-radius:10px;font-size:23px}
.rates-pathway .fraction-lesson-directory .linear-lesson-list{display:grid;grid-template-columns:1fr;gap:0;margin:0;padding:0}
.rates-pathway .fraction-lesson-directory .linear-lesson-list>a{display:grid;grid-template-columns:30px minmax(0,1fr) 18px;align-items:center;min-height:54px;gap:12px;padding:12px 5px;border-bottom:1px solid var(--line);border-radius:0}
.rates-pathway .fraction-lesson-directory .linear-lesson-list>a:last-child{border-bottom:0}
.rates-pathway .fraction-lesson-directory .linear-lesson-list>a>b{display:grid;place-items:center;width:29px;min-width:29px;height:29px;font-size:11px;font-weight:700;border-radius:7px;color:var(--muted);background:var(--soft)}
.rates-pathway .fraction-lesson-directory .linear-lesson-list strong{font-size:14px;line-height:1.45}
.rates-pathway .fraction-lesson-directory .linear-lesson-list .icon{width:17px;height:17px;min-width:17px;margin:0;color:var(--blue)}
.rates-pathway .fraction-lesson-directory .linear-lesson-list>a:hover{background:var(--soft)}
.rates-pathway .fraction-lesson-directory .linear-lesson-list>a:hover strong{text-decoration:none;color:var(--blue)}
.rates-pathway .hub-jumps{display:flex;justify-content:center;align-items:center;gap:8px;padding:12px 0 18px;margin:0 0 8px}
.rates-pathway .hub-jumps a{display:inline-flex;justify-content:center;align-items:center;min-height:42px;padding:9px 15px;border:1px solid var(--line);border-radius:9px;background:var(--paper);color:var(--ink);font-size:12px;line-height:1.4;text-align:center}
.rates-pathway .hub-jumps a:hover{border-color:var(--blue);color:var(--blue);background:var(--soft)}
.rates-pathway .rates-project{padding:28px 24px;margin:22px 0 28px}
.rates-pathway .rates-project p{font-size:15px;line-height:1.7;margin:13px auto 20px}
.rates-pathway .project-actions{display:flex;flex-wrap:wrap;justify-content:center;align-items:stretch;gap:10px;max-width:570px;margin:0 auto}
.rates-pathway .rates-project .project-actions a{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:11px 16px;margin:0;border:1px solid #8baecf;border-radius:9px;font-size:13px;font-weight:650;line-height:1.4;text-align:center}
.rates-pathway .project-actions a:first-child{flex:1 0 100%;background:#fff;color:#163e66;border-color:#fff}
.rates-pathway .project-actions a:not(:first-child){flex:1 1 180px;background:#ffffff0a}
.rates-pathway .project-actions a:hover{background:#dcecff;color:#163e66}
.rates-pathway .learning-collection{padding:24px 18px}
.rates-pathway .learning-collection nav{gap:9px 12px;margin-top:15px}
.rates-pathway .learning-collection nav a{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:9px 13px;border:1px solid var(--line);border-radius:8px;background:var(--paper);font-size:13px;line-height:1.5;text-decoration:none;max-width:100%;text-align:center}
.rates-pathway .learning-collection nav a:hover{border-color:var(--blue);background:var(--soft)}
.rates-pathway .unit-companion nav a{padding:9px 8px;gap:10px;min-height:43px;border-radius:7px}
.rates-pathway .unit-companion .reading-guide nav a{padding:10px 8px!important}
.rates-pathway .unit-companion section>h2{margin-bottom:13px}
.rates-pathway .unit-companion .reference-key>a{display:flex;align-items:center;min-height:42px;padding:8px 0;font-size:12px}
.rates-pathway .inline-notes{padding:20px 22px}
.rates-pathway .inline-notes a,.rates-pathway .inline-notes button{display:inline-flex;align-items:center;justify-content:center;min-height:44px;margin:5px 8px 0 0;padding:10px 14px;border-radius:8px;border:1px solid #a9bfd5;background:var(--paper);color:var(--blue);font-size:12px;font-weight:650;line-height:1.4;text-decoration:none}
.rates-pathway .lp-actions{align-items:stretch;gap:10px}
.rates-pathway .lp-actions button{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:11px 15px;line-height:1.4;border-radius:8px}
.rates-pathway .lp-form .lp-actions>.text-button{flex-basis:100%;justify-content:flex-start;padding-left:0;min-height:36px}
.rates-pathway .rm-controls{gap:14px;align-items:end}
.rates-pathway .rm-controls label{font-size:13px;line-height:1.5;gap:7px}
.rates-pathway .rm-controls input{height:44px;border-radius:8px;padding:10px 12px;font-size:14px}
.dark .rates-pathway .fraction-lesson-chapter{background:var(--paper);border-color:var(--line)}
@media(max-width:700px){.rates-pathway .unit-lesson-section{padding:20px 14px}.rates-pathway .fraction-lesson-chapter{padding:16px 12px 5px}.rates-pathway .fraction-lesson-chapter h3{font-size:17px}.rates-pathway .fraction-lesson-directory .linear-lesson-list>a{min-height:54px;gap:9px;padding:12px 1px}.rates-pathway .hub-jumps{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.rates-pathway .hub-jumps a{padding:10px 8px;font-size:12px}.rates-pathway .hub-jumps a:last-child:nth-child(odd){grid-column:1/-1}.rates-pathway .rates-project{padding:24px 16px}.rates-pathway .project-actions a{flex-basis:100%!important}.rates-pathway .learning-collection{padding:21px 14px}.rates-pathway .learning-collection nav{display:grid;grid-template-columns:1fr;gap:8px}.rates-pathway .learning-collection nav a{width:100%;padding:11px 12px}.rates-pathway .lp-form .lp-actions>.primary,.rates-pathway .lp-form .lp-actions>.secondary{flex:1 1 140px}.rates-pathway .inline-notes{padding:18px 16px}}