:root{--forest:#043a2f;--forest-2:#0b5847;--ink:#102a24;--muted:#64746f;--line:#dbe4e0;--soft:#f3f7f5;--paper:#fff;--amber:#af6d12;--green:#15805f;--red:#a2473e;--shadow:0 12px 35px #0a352b14;color:var(--ink);font-synthesis:none;background:#fff;font-family:Atkinson Hyperlegible,system-ui,sans-serif}*{box-sizing:border-box}html,body,#root{background:#fff;min-height:100%;margin:0}body{font-size:16px;line-height:1.5}button,input,textarea{font:inherit;color:inherit}button{cursor:pointer}.topbar{border-bottom:1px solid var(--line);z-index:30;background:#fff;align-items:center;height:74px;padding:0 36px;display:flex;position:sticky;top:0}.wordmark{color:var(--forest);align-items:center;gap:10px;line-height:1;text-decoration:none;display:flex}.wordmark strong{letter-spacing:.11em;font-size:17px;display:block}.wordmark small{color:var(--muted);letter-spacing:.06em;margin-top:5px;font-size:11px;display:block}.mark{background:var(--forest);color:#fff;border-radius:5px 10px;place-items:center;width:32px;height:32px;font-family:Georgia,serif;font-size:20px;display:grid}.topbar-tools{align-items:center;gap:16px;margin-left:auto;display:flex}.search{border-bottom:1px solid var(--line);width:255px;height:40px;color:var(--muted);align-items:center;gap:8px;display:flex}.search input{background:0 0;border:0;outline:0;width:100%;font-size:14px}.quiet,.icon-button,.mobile-menu,.rail-close,.avatar,.check-button,.lightbox-close{background:0 0;border:0}.quiet{color:var(--forest);align-items:center;gap:7px;font-size:14px;display:flex}.counter{color:var(--muted);font-size:12px}.avatar{width:34px;height:34px;color:var(--forest);background:#e2ebe7;border-radius:50%;font-weight:700}.mobile-menu{display:none}.layout{min-height:calc(100vh - 74px);display:flex}.topic-rail{border-right:1px solid var(--line);background:#fff;flex-direction:column;flex:0 0 267px;width:267px;height:calc(100vh - 74px);padding:26px 16px 20px;display:flex;position:sticky;top:74px}.rail-head{letter-spacing:.11em;text-transform:uppercase;color:var(--muted);justify-content:space-between;padding:0 13px 14px;font-size:12px;display:flex}.rail-close{display:none}.rail-list{padding-right:4px;overflow:auto}.rail-list button{text-align:left;color:#4d625b;background:0 0;border:0;border-radius:5px;align-items:center;gap:10px;width:100%;min-height:44px;padding:8px 10px;font-size:14px;line-height:1.2;display:flex}.rail-list button:hover{background:var(--soft)}.rail-list button.selected{color:var(--forest);background:#eaf3ef;font-weight:700}.rail-list svg{margin-left:auto}.topic-number{color:#8b9f98;letter-spacing:.06em;width:20px;font-size:11px}.selected .topic-number{color:var(--forest)}.rail-footer{border-top:1px solid var(--line);color:var(--muted);align-items:center;gap:8px;margin-top:auto;padding:16px 10px 0;font-size:12px;display:flex}.status-dot{background:#d49334;border-radius:50%;width:7px;height:7px}.main{width:100%;max-width:1450px;margin:0 auto;padding:29px 42px 80px}.crumb{color:var(--muted);letter-spacing:.03em;margin-bottom:24px;font-size:12px}.crumb span{color:var(--forest)}.preview-note{color:#805211;background:#fff8e9;border:1px solid #eed6a8;align-items:center;gap:7px;margin-bottom:18px;padding:8px 11px;font-size:13px;display:flex}.topic-header{border-bottom:1px solid var(--line);padding-bottom:26px}.topic-header-row{justify-content:space-between;gap:30px;display:flex}.section-kicker,.callout-label{text-transform:uppercase;letter-spacing:.14em;color:var(--forest-2);margin:0 0 8px;font-size:11px;font-weight:700}.topic-header h1,.review-hero h2,.viva-intro h2,.view-intro h2,.practice-callout h2{color:var(--forest);letter-spacing:-.025em;margin:0;font:400 42px/1.11 Georgia,serif}.lede{color:#596d66;max-width:700px;margin:14px 0 0;font-size:17px;line-height:1.58}.topic-actions{align-items:flex-start;gap:12px;padding-top:26px;display:flex}.icon-button{border:1px solid var(--line);color:#779088;border-radius:4px;place-items:center;width:44px;height:44px;display:grid}.icon-button.active{color:#b27a18;background:#fff9ee;border-color:#e3c68e}.outline-button,.solid-button{border-radius:4px;align-items:center;gap:10px;height:44px;padding:0 16px;font-size:14px;font-weight:700;display:inline-flex}.outline-button{color:var(--forest);background:#fff;border:1px solid #86a59b}.outline-button:hover{background:var(--soft)}.solid-button{border:1px solid var(--forest);background:var(--forest);color:#fff}.topic-meta{color:var(--muted);align-items:center;gap:10px;margin-top:24px;font-size:13px;display:flex}.review-label{color:var(--amber);margin-left:auto}.content-grid{grid-template-columns:minmax(0,1fr) 250px;gap:56px;display:grid}.section-nav{border-bottom:1px solid var(--line);white-space:nowrap;gap:23px;display:flex;overflow:auto}.section-nav button{color:#75837e;background:0 0;border:0;padding:18px 0 14px;font-size:14px;position:relative}.section-nav button.active{color:var(--forest);font-weight:700}.section-nav button.active:after{content:"";background:var(--forest);height:2px;position:absolute;bottom:-1px;left:0;right:0}.nav-mark{vertical-align:top;background:#d49334;border-radius:50%;width:5px;height:5px;margin-left:5px;display:inline-block}.learn-view,.visual-view,.viva-view,.papers-view,.practice-view,.review-view{padding-top:35px}.intro-line{align-items:center;gap:14px;margin-bottom:30px;display:flex}.intro-line p{color:var(--muted);margin:0;font-size:14px}.rule{background:var(--forest);width:35px;height:1px}.learn-section{grid-template-columns:65px minmax(0,700px);gap:14px;margin-bottom:35px;display:grid}.section-index{color:#95a59f;letter-spacing:.1em;padding-top:5px;font-size:12px}.learn-section h2{color:var(--forest);margin:0 0 10px;font:400 26px/1.2 Georgia,serif}.learn-section p{color:#536761;margin:0;font-size:16px;line-height:1.65}.learn-section ul{color:#536761;padding-left:20px}.learn-section li{margin:7px 0}.practice-callout,.viva-intro,.review-hero{background:var(--soft);justify-content:space-between;align-items:center;gap:24px;margin-top:40px;padding:27px 28px;display:flex}.practice-callout h2{margin-bottom:7px;font-size:26px}.practice-callout p,.review-hero p{color:#5d7069;margin:0}.visual-view,.papers-view,.practice-view{max-width:850px}.view-count{color:var(--forest-2);text-transform:uppercase;letter-spacing:.12em;margin-bottom:10px;font-size:12px;font-weight:700;display:block}.view-intro h2{font-size:31px}.view-intro .muted{color:#8a9994;font-size:22px}.view-intro p{color:var(--muted);max-width:630px;margin:12px 0 27px}.visual-list{gap:20px;display:grid}.visual-card{border-top:1px solid var(--line);grid-template-columns:240px 1fr;gap:22px;padding-top:20px;display:grid}.visual-media{background:#eaf1ee;border:0;place-items:center;height:170px;padding:0;display:grid;overflow:hidden}.visual-media:disabled{cursor:default}.visual-media img{object-fit:cover;width:100%;height:100%}.visual-media span{color:#9bafa7}.visual-copy .card-overline,.card-overline{letter-spacing:.11em;color:#789088;text-transform:uppercase;font-size:11px}.visual-copy h3{color:var(--forest);margin:7px 0;font:400 21px/1.25 Georgia,serif}.visual-copy>p{color:#536761;margin:0 0 12px}.visual-copy details{border-top:1px solid var(--line);color:#536761;padding-top:10px;font-size:14px}.visual-copy summary{color:var(--forest);cursor:pointer;font-weight:700}.visual-copy details p{margin:8px 0}.lightbox{z-index:100;background:#041c16db;place-items:center;padding:30px;display:grid;position:fixed;inset:0}.lightbox-inner{color:#fff;max-width:min(1000px,95vw);position:relative}.lightbox-inner img{max-width:100%;max-height:76vh;margin:auto;display:block}.lightbox-inner p{text-align:center;margin:12px 0}.lightbox-close{color:#fff;width:34px;height:34px;position:absolute;top:-35px;right:-35px}.viva-intro{margin:0 0 25px}.viva-intro h2{font-size:30px}.viva-intro p{color:#5d7069;margin:8px 0 0}.viva-score{text-align:center;border-left:1px solid #d1ded8;padding-left:28px}.viva-score strong{color:var(--forest);font:400 38px Georgia,serif;display:block}.viva-score span{color:var(--muted);text-transform:uppercase;letter-spacing:.1em;font-size:12px}.viva-station{border-top:1px solid var(--line);padding:21px 0}.station-head{grid-template-columns:40px 1fr 40px;align-items:start;gap:13px;display:grid}.station-number{color:#91a39b;letter-spacing:.08em;padding-top:5px;font-size:12px}.station-head h3{color:var(--forest);margin:6px 0 0;font:400 20px/1.35 Georgia,serif}.check-button{color:#91a39b;border:1px solid #cbdad4;border-radius:50%;width:32px;height:32px;font-size:17px}.check-button.done{background:var(--forest);color:#fff;border-color:var(--forest)}.station-actions{align-items:center;gap:18px;margin:13px 0 0 53px;display:flex}.text-button,.reveal-link{color:var(--forest);background:0 0;border:0;align-items:center;gap:7px;padding:0;font-size:14px;font-weight:700;display:inline-flex}.text-button svg{transform:rotate(90deg)}.expanded .text-button svg{transform:rotate(-90deg)}.source-tag{color:var(--muted);font-size:12px}.station-answer{border-left:2px solid #bdd3c9;margin:17px 0 0 53px;padding:3px 0 4px 19px}.opening{color:#4d635b;margin:0 0 15px}.answer-step{align-items:baseline;gap:10px;display:flex}.answer-step span{color:#8ca099;font-size:13px}.answer-step p{color:#536761;margin:4px 0}.followups{border-top:1px solid var(--line);margin-top:15px;padding-top:12px}.followups h4{text-transform:uppercase;letter-spacing:.1em;color:var(--forest);margin:0;font-size:12px}.followups ul{color:#536761;margin:8px 0;padding-left:18px}.pitfall{color:#765420;background:#fff8e9;padding:10px 12px;font-size:14px}.paper-list{border-top:1px solid var(--line)}.paper-row{text-align:left;border:0;border-bottom:1px solid var(--line);width:100%;color:var(--forest);background:#fff;grid-template-columns:60px 1fr 22px;align-items:center;gap:13px;padding:17px 3px;display:grid}.paper-row:hover{background:var(--soft)}.paper-year{letter-spacing:.08em;color:var(--forest-2);font-size:12px}.paper-row strong{font:400 17px Georgia,serif;display:block}.paper-row small{color:var(--muted);margin-top:4px;font-size:13px;display:block}.question-card{border-top:1px solid var(--line);padding:23px 0 19px}.question-meta{text-transform:uppercase;letter-spacing:.1em;color:#789088;gap:13px;font-size:11px;display:flex}.question-card h3{color:var(--forest);margin:10px 0 17px;font:400 21px/1.4 Georgia,serif}.question-options{gap:7px;display:grid}.question-options button{text-align:left;background:#fff;border:1px solid #d8e3df;align-items:flex-start;gap:12px;padding:11px 13px;font-size:15px;line-height:1.4;display:flex}.question-options button:hover:not(:disabled){background:var(--soft);border-color:#86a59b}.question-options b{color:var(--forest);min-width:15px;font-size:13px}.question-options button.correct{background:#eef8f1;border-color:#7db79f}.question-options button.wrong{background:#fff1ef;border-color:#d8988f}.question-options button.dim{opacity:.52}.question-explanation{border-left:2px solid var(--forest);color:#536761;margin-top:16px;padding:8px 0 8px 15px}.question-explanation strong{color:var(--forest)}.question-explanation p{margin:7px 0}.teaching-point{color:var(--forest-2);font-weight:700}.reveal-link{color:#5d7169;margin-top:11px;font-weight:400}.empty-state{border-top:1px solid var(--line);color:#8a9b95;padding:40px 0}.empty-state svg{color:#9bafa7}.empty-state h3{color:var(--forest);margin:10px 0 5px;font:400 22px Georgia,serif}.empty-state p{max-width:520px;margin:0}.review-hero{margin:0;display:block}.review-hero h2{max-width:650px;font-size:31px}.review-hero p{max-width:650px;margin-top:12px}.review-grid{background:var(--line);grid-template-columns:repeat(3,1fr);gap:1px;margin-top:25px;display:grid}.review-stat{background:#fff;padding:22px}.review-stat strong{color:var(--forest);font:400 31px Georgia,serif;display:block}.review-stat span{color:var(--muted);margin-top:4px;font-size:13px;display:block}.review-actions{gap:12px;margin-top:23px;display:flex}.context-rail{padding-top:74px}.context-card{border-top:2px solid var(--forest);padding:15px 0 21px}.context-label{text-transform:uppercase;letter-spacing:.11em;color:var(--forest-2);align-items:center;gap:7px;font-size:11px;font-weight:700;display:flex}.progress-ring{border:7px solid #dcebe4;border-top-color:var(--forest);border-radius:50%;place-items:center;width:78px;height:78px;margin:17px 0 10px;display:grid}.progress-ring strong{color:var(--forest);font:400 23px Georgia,serif}.progress-card p{color:var(--muted);margin:0;font-size:14px}.note-card{border-top:1px solid var(--line)}.note-card textarea{resize:vertical;border:1px solid var(--line);outline:none;width:100%;min-height:105px;margin:12px 0 7px;padding:10px;font-size:14px;line-height:1.4;display:block}.note-card textarea:focus{border-color:#86a59b}.save-hint{color:#9aa9a3;font-size:11px}.context-link{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:15px 0}.context-link span{text-transform:uppercase;letter-spacing:.11em;color:var(--muted);margin-bottom:8px;font-size:11px;display:block}.context-link button{color:var(--forest);background:0 0;border:0;align-items:center;gap:8px;padding:0;font-size:14px;font-weight:700;display:flex}.context-foot{color:#94a39e;margin-top:18px;font-size:11px;line-height:1.45}@media (width<=1100px){.topic-rail{flex-basis:230px;width:230px}.main{padding-left:29px;padding-right:29px}.content-grid{grid-template-columns:minmax(0,1fr) 210px;gap:30px}.search{width:190px}}@media (width<=760px){.topbar{height:66px;padding:0 16px}.mobile-menu{width:42px;height:42px;color:var(--forest);place-items:center;margin-right:7px;display:grid}.topbar-tools{gap:8px}.topbar-tools .search,.topbar-tools .quiet{display:none}.topic-rail{z-index:50;width:min(320px,90vw);height:auto;box-shadow:var(--shadow);padding-top:24px;display:none;position:fixed;inset:66px auto 0 0}.topic-rail.open{display:flex}.rail-close{color:var(--muted);display:block}.layout{display:block}.main{padding:20px 17px 54px}.crumb{margin-bottom:17px}.topic-header-row{display:block}.topic-header h1{font-size:34px}.lede{font-size:16px}.topic-actions{padding-top:18px}.topic-meta{flex-wrap:wrap;gap:6px 8px}.review-label{width:100%;margin-left:0;padding-top:4px}.content-grid{display:block}.context-rail{display:none}.section-nav{gap:19px}.section-nav button{font-size:13px}.learn-view,.visual-view,.viva-view,.papers-view,.practice-view,.review-view{padding-top:28px}.learn-section{grid-template-columns:37px 1fr;gap:8px;margin-bottom:28px}.learn-section h2{font-size:23px}.practice-callout,.viva-intro{margin-top:27px;padding:21px;display:block}.practice-callout h2,.viva-intro h2,.review-hero h2,.view-intro h2{font-size:26px}.practice-callout .solid-button{margin-top:18px}.visual-card{grid-template-columns:1fr;gap:15px}.visual-media{height:200px}.station-head{grid-template-columns:29px 1fr 34px;gap:8px}.station-actions,.station-answer{margin-left:37px}.station-head h3{font-size:18px}.viva-score{text-align:left;border-top:1px solid #d1ded8;border-left:0;align-items:baseline;gap:10px;margin-top:20px;padding:13px 0 0;display:flex}.viva-score strong{font-size:28px}.paper-row{grid-template-columns:47px 1fr 18px}.review-grid{grid-template-columns:1fr}.review-actions{display:grid}.outline-button{justify-content:center}.lightbox{padding:15px}.lightbox-close{top:-42px;right:-5px}.topic-number{width:18px}}@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}.topbar{background:var(--forest);color:#fff;border-bottom-color:#ffffff24;height:62px}.wordmark{color:#fff}.wordmark small{color:#ffffffb3}.mark{color:var(--forest);background:#fff;border-radius:7px 11px}.top-nav{align-items:stretch;gap:30px;height:100%;margin-left:clamp(28px,7vw,100px);display:flex}.top-nav a{color:#ffffffe6;border-bottom:3px solid #0000;align-items:center;padding:2px 0 0;font-size:15px;text-decoration:none;display:flex}.top-nav a:hover,.top-nav a:focus-visible{color:#fff;border-bottom-color:#fff}.topbar-tools .search{color:#ffffffdb;border-bottom-color:#ffffff61}.topbar-tools .search input,.topbar-tools .quiet{color:#fff}.topbar-tools .search input::placeholder{color:#ffffffb3}.topbar-tools .quiet:hover,.topbar-tools .quiet:focus-visible{color:#fff}.avatar{color:#fff;background:#ffffff2e}.topic-rail{height:calc(100vh - 62px);top:62px}.main{padding-top:34px}.topic-header h1{color:#0f231f}.topic-header{padding-bottom:25px}.section-nav{z-index:15;background:#fff;position:sticky;top:62px}.knowledge-media{background:var(--soft);place-items:center;min-height:140px;display:grid;overflow:hidden}.knowledge-media img{object-fit:cover;width:100%;height:100%;min-height:140px;display:block}.knowledge-copy>p{color:#536761;margin:0 0 10px}.knowledge-qa details{border-bottom:1px solid var(--line);color:#536761;padding:10px 0}.knowledge-qa div{margin-top:8px;font-size:14px;line-height:1.5}.knowledge-qa p{margin:4px 0}.visual-context{color:#6c7d77;border-left:2px solid #d3e0db;padding-left:10px;font-size:13px;line-height:1.45;margin:10px 0!important}.question-images{flex-wrap:wrap;gap:10px;margin:0 0 14px;display:flex}.question-images img{object-fit:contain;border:1px solid var(--line);background:#f5f7f6;width:auto;max-width:100%;max-height:190px;display:block}.formatted-explanation{margin-top:8px}.formatted-explanation p{white-space:pre-wrap;margin:7px 0}.formatted-explanation h4{color:var(--forest);margin:13px 0 7px;font-size:14px}.explanation-gap{height:4px}.explanation-bullet{padding-left:4px}.explanation-table-line{color:#536761;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px}.global-papers .paper-row{grid-template-columns:170px 1fr 22px}.global-papers .paper-year{font-size:11px}.related-card{border-top:1px solid var(--line);padding-bottom:8px}.context-row{border:0;border-bottom:1px solid var(--line);width:100%;color:var(--forest);text-align:left;background:#fff;justify-content:space-between;align-items:center;padding:11px 0;font-size:13px;display:flex}.context-row:hover{color:var(--forest-2)}.rail-search{border:1px solid var(--line);height:42px;color:var(--muted);align-items:center;gap:8px;margin:0 0 13px;padding:0 11px;display:flex}.rail-search input{background:0 0;border:0;outline:0;width:100%;font-size:14px}.rail-search input::placeholder{color:#8a9994}.rail-empty{color:var(--muted);padding:12px;font-size:13px}@media (width<=900px){.top-nav{display:none}.topbar{padding:0 18px}.topic-rail{height:calc(100vh - 62px);top:62px}.section-nav{top:62px}}@media (width<=760px){.topbar{height:66px}.mobile-menu{color:#fff}.topic-rail{height:calc(100vh - 66px);top:66px}.section-nav{top:66px}.knowledge-card{grid-template-columns:1fr}.knowledge-media,.knowledge-media img{min-height:180px}.global-papers .paper-row{grid-template-columns:95px 1fr 18px}}.book-tools{align-items:center;gap:10px;margin:18px 0 6px;display:flex}.book-tools label{border:1px solid var(--line);height:43px;color:var(--muted);flex:1;align-items:center;gap:8px;padding:0 11px;display:flex}.book-tools input{border:0;outline:0;width:100%;font-size:14px}.book-tools select{border:1px solid var(--line);height:43px;color:var(--forest);background:#fff;padding:0 11px;font-size:14px}.emq-scenario{color:var(--muted);margin:0 0 15px}.emq-options{border-top:1px solid var(--line);border-bottom:1px solid var(--line);flex-wrap:wrap;gap:6px;margin-bottom:9px;padding:12px 0;display:flex}.emq-options span{color:#536761;padding-right:9px;font-size:13px}.emq-options b{color:var(--forest);margin-right:5px}.emq-leadin{border-bottom:1px solid #edf1ef;padding:11px 0}.emq-leadin p{color:#536761;margin:0 0 5px;font-size:14px}.emq-leadin>p:first-child strong{color:var(--forest)}.emq-explanation{border-left:2px solid var(--forest);padding-left:11px;margin-top:9px!important}.review-topic-list{border-top:1px solid var(--line);margin-top:25px}.review-topic-list button{text-align:left;border:0;border-bottom:1px solid var(--line);width:100%;color:var(--forest);background:#fff;grid-template-columns:1fr auto 20px;align-items:center;gap:13px;padding:15px 4px;display:grid}.review-topic-list button:hover{background:var(--soft)}.review-topic-list small{color:var(--muted);font-size:12px}@media (width<=760px){.book-tools{grid-template-columns:1fr;display:grid}.book-tools select{width:100%}.review-topic-list button{grid-template-columns:1fr 20px}.review-topic-list small{display:none}}.knowledge-view{max-width:900px}.knowledge-card{border-top:1px solid var(--line);grid-template-columns:220px 1fr;gap:22px;padding:20px 0;display:grid}.knowledge-media{background:var(--soft);color:#9bafa7;place-items:center;height:150px;display:grid;overflow:hidden}.knowledge-media img{object-fit:cover;width:100%;height:100%}.knowledge-copy h3{color:var(--forest);margin:7px 0;font:400 21px/1.25 Georgia,serif}.knowledge-copy>p{color:#536761;margin:0 0 11px;font-size:14px}.knowledge-qa{border-top:1px solid var(--line);margin-top:10px}.knowledge-qa details{border-bottom:1px solid var(--line);color:#536761;padding:9px 0;font-size:14px}.knowledge-qa summary{cursor:pointer;color:var(--forest);font-weight:700}.knowledge-qa details div{padding:8px 0 0}.knowledge-qa ul{margin:3px 0;padding-left:19px}.muted-copy{color:var(--muted)!important}.rich-answer{color:#536761}.rich-answer p{margin:7px 0}.rich-answer ul{color:#536761;margin:7px 0;padding-left:19px}.answer-text{white-space:pre-line;color:#536761}.emq-card h3{margin-bottom:8px}@media (width<=760px){.knowledge-card{grid-template-columns:1fr;gap:15px}.knowledge-media{height:190px}}