@font-face{font-family:Golos;src:url('fonts/GolosText.woff2') format('woff2');font-style:normal;font-weight:400 900;font-display:swap}
:root{--bg:#f7f9fa;--ink:#182b31;--muted:#65747b;--line:#dce4e7;--green:#08796d;--lime:#e5f4ee;--orange:#9a5a22;--radius:16px;--shadow:0 6px 22px #183a4510}
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small{font-size:10px;letter-spacing:0;font-weight:500;margin-top:4px;color:var(--muted)}.brand-mark{width:43px;height:43px;border-radius:13px;background:var(--green);color:#fff;display:grid;place-items:center;font-size:38px;line-height:1;font-weight:500;padding-bottom:5px}.ui-icon{width:20px;height:20px;flex:0 0 20px;vertical-align:middle}.brand .ui-icon{width:26px;height:26px}#appNav{margin-left:auto;display:flex;gap:7px;align-items:center}.nav-item{display:flex;align-items:center;gap:8px;padding:11px 15px;font-size:13px;font-weight:500;border-radius:10px;min-height:44px}.nav-item:hover{background:#edf2f3}.nav-item.active{background:#dff0eb;color:#075d54}.nav-item.active .ui-icon{filter:invert(27%) sepia(23%) saturate(1960%) hue-rotate(123deg) brightness(90%)}#openMap{position:absolute;right:40px;top:117px;font-size:12px;padding:9px 13px;min-height:40px}.intro{padding:32px 0 25px}.intro h1{font-size:36px;line-height:1.18;font-weight:650;letter-spacing:-1.25px;margin:8px 0 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h2{font-size:22px;font-weight:600;line-height:1.3;margin:0}.section-label>span{font-size:12px;color:var(--muted)}.today-layout{display:grid;grid-template-columns:minmax(0,1fr) 286px;gap:26px}.continue-panel{background:#fff;border:1px solid var(--line);border-radius:18px;padding:28px;box-shadow:var(--shadow)}.panel-kicker{display:flex;gap:8px;align-items:center;font-size:12px;color:var(--muted);font-weight:500}.panel-kicker .ui-icon{height:17px;width:17px;flex-basis:17px}.continue-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin:25px 0}.continue-heading h2{font-size:30px;line-height:1.2;font-weight:650;margin:0 0 8px}.continue-heading p{font-size:14px;color:var(--muted);margin:0;max-width:420px}.large-symbol{display:grid;place-items:center;min-width:92px;height:92px;border-radius:22px;background:#e6f3ef;color:#08796d;font-size:35px;font-weight:600;letter-spacing:-2px}.continue-meta{display:flex;flex-wrap:wrap;gap:8px 18px;font-size:11px;color:var(--muted);padding-bottom:23px}.continue-meta span{color:#416b61}.panel-actions{display:flex;flex-wrap:wrap;gap:10px}.daily-review{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:15px;align-items:center;background:#e9f3f1;border-radius:14px;padding:20px;margin-top:16px}.round-icon{display:grid;place-items:center;width:43px;height:43px;border-radius:50%;background:#fff}.daily-review h2{font-size:16px;font-weight:600;margin:0 0 4px}.daily-review p{font-size:12px;line-height:1.6;color:#57726c;margin:0}.daily-review .subtle{font-size:12px;padding:9px 13px;min-height:42px;background:#fff;border-color:#ccded8}.small-panel{padding:23px;background:#fff;border:1px solid var(--line);border-radius:15px;margin:0 0 18px}.small-panel h2{font-size:17px;line-height:1.35;font-weight:600;margin:0 0 12px}.small-panel .panel-kicker+h2{margin-top:14px}.small-panel p{font-size:13px;line-height:1.7;color:var(--muted);margin:8px 0 18px}.small-panel 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0}.topic-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px}.topic-tile{position:relative;display:grid;grid-template-columns:64px minmax(0,1fr);column-gap:18px;background:#fff;border:1px solid var(--line);border-radius:15px;padding:24px;transition:box-shadow .15s,border-color .15s,transform .15s;min-width:0}.topic-tile:hover{border-color:#75b4a9;box-shadow:0 5px 20px #1d65500c;transform:translateY(-2px)}.topic-symbol{display:grid;place-items:center;width:64px;height:64px;border-radius:14px;background:#eaf4f1;color:var(--green);font-size:25px;font-weight:600;letter-spacing:-1px;flex:0 0 64px}.topic-copy h3{font-size:20px;line-height:1.3;font-weight:600;margin:0 0 10px}.topic-copy p{font-size:12px;line-height:1.65;color:var(--muted);margin:0 0 14px}.topic-meta{font-size:11px;color:#6a7c82;display:flex;gap:7px 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input{border:0;background:none;outline:none;min-width:0;width:100%;font-size:14px;color:var(--ink)}.search-box:focus-within{border-color:var(--green);box-shadow:0 0 0 3px #08796d14}.topic-overview{background:#fff;border:1px solid var(--line);border-radius:18px;padding:27px;box-shadow:var(--shadow)}.topic-overview-main{display:flex;gap:19px;align-items:center;margin-bottom:24px}.topic-overview-main h2{font-size:23px;font-weight:600;line-height:1.3;margin:0 0 5px}.topic-overview-main p{font-size:13px;color:var(--muted);margin:0}.topic-status{display:flex;gap:13px 25px;align-items:center;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:18px;margin-top:24px;font-size:12px;color:var(--muted)}.topic-status b{color:var(--ink);font-weight:550}.topic-status>a{margin-left:auto;font-size:12px}.topic-detail-grid{display:grid;grid-template-columns:minmax(0,1fr) 286px;gap:30px}.topic-detail-grid>aside{padding-top:30px}.chapter-list{background:#fff;border:1px solid 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button:hover{background:#e7f3ef;border-color:#a8cfc4}.kind-actions{display:flex;gap:8px;margin-top:14px}.kind-actions button{flex:1;border-radius:8px;background:#edf5f2;color:#116d60;padding:10px 7px;font-size:12px;min-height:42px}.small-panel ul{padding-left:18px;font-size:12px;color:var(--muted);line-height:1.8}.small-panel li+li{margin-top:7px}.practice-modes{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:17px}.mode-tile{display:grid;grid-template-columns:48px minmax(0,1fr);gap:0 17px;background:#fff;border:1px solid var(--line);border-radius:15px;padding:25px;transition:border-color .15s}.mode-tile:hover{border-color:#65ad9f;background:#fcfffd}.mode-icon{grid-row:1/4;display:grid;place-items:center;background:#e9f4f0;border-radius:12px;width:48px;height:48px}.mode-icon .ui-icon{width:25px;height:25px}.mode-tile h2{font-size:21px;font-weight:600;line-height:1.3;margin:0 0 9px}.mode-tile p{font-size:13px;color:var(--muted);margin:0 0 20px}.mode-cta{display:flex;justify-content:space-between;color:var(--green);font-size:12px;font-weight:550}.practice-topic-list{background:#fff;border:1px solid var(--line);border-radius:15px;overflow:hidden}.practice-topic-list>a{display:grid;grid-template-columns:44px minmax(0,1fr) auto;align-items:center;gap:16px;padding:17px 23px}.practice-topic-list>a+a{border-top:1px solid #e8edef}.practice-topic-list>a:hover{background:#f0f7f5}.mini-symbol{background:#f0f5f3;color:var(--green);border-radius:10px;height:43px;display:grid;place-items:center;font-size:17px;font-weight:550;letter-spacing:-.7px}.practice-topic-list strong{font-size:14px;font-weight:550}.practice-topic-list small{display:block;font-size:11px;color:var(--muted);margin-top:4px}.practice-topic-list>a>span:last-child{display:flex;gap:7px;align-items:center;font-size:12px;color:var(--green)}
/* Practice surfaces share the same button, type and spacing system. */
.task-card{border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);animation:none}.card-inner{padding:30px 34px}.task-card h2{font-family:Golos,Arial,sans-serif;font-weight:600;font-size:25px;letter-spacing:-.65px;line-height:1.35;margin:21px 0 10px}.card-meta{font-size:12px}.tag{border:0;background:#f0f4f5;border-radius:6px;padding:5px 9px;font-size:11px;color:#557078}.tag.level{background:#e9f4ef;color:#156b56;border:0}.instruction{font-size:13px;line-height:1.7;color:var(--muted);margin-bottom:13px}.equation{background:#f4f7f8;border:1px solid #e8eef0;border-radius:12px;min-height:130px;padding:25px 20px;column-gap:12px;row-gap:9px}.species img{height:58px}.answer-box .species img{height:54px}.condition{font-size:12px;line-height:1.65;margin-top:12px}.condition strong{font-weight:500}.theory-link{font-size:12px;padding:0 0 18px;min-height:34px;font-weight:500}.actions{gap:12px;margin-top:22px}.hint-box,.answer-box{border-radius:12px;padding:22px;margin-top:22px}.hint-box{background:#fff8e8;border-color:#ebdcb6}.answer-box{background:#edf7f2;border-color:#cce4d9}.answer-box .equation{border:0;border-radius:0;padding:12px 0;min-height:85px}.answer-box p{font-size:14px;line-height:1.8}.box-label{font-size:11px;letter-spacing:.04em}.card-bottom{padding:16px 34px;background:#fafcfc;border-color:#e5ecee;gap:15px}.nav-button{border-radius:9px;padding:10px 15px;font-size:13px;min-height:44px}.nav-button:hover:not(:disabled){background:#e8f2ee}.nav-button:last-child{background:#e8f3ee;color:#0c695b}.self-actions{gap:10px}.self-actions button{min-height:46px;font-size:13px;font-weight:500;border-radius:9px;padding:11px 13px;border-color:#c7d9d1}.self-actions .selected-good{background:var(--green);border-color:var(--green)}.self-actions .selected-retry{background:#f8e7d3;color:#7b4a1d;border-color:#d5aa74}.assist-check{font-size:12px;line-height:1.6;margin:12px 0}.self-label{font-size:12px}.error-picker{padding-top:18px}.error-options{gap:10px 16px}.error-options label{background:#fff;padding:8px 10px;border-radius:8px;border:1px solid #dce4df}.rating-note{font-size:12px!important;line-height:1.7}.task-sources{font-size:12px}.task-sources summary{padding:7px 0;min-height:36px}.task-sources a{text-decoration:underline;text-underline-offset:3px}.source-scope{line-height:1.6}.draft{margin-top:20px}.draft summary{font-size:12px;min-height:34px}.draft textarea{font-size:15px;line-height:1.7}.controls{display:flex;align-items:end;border-top:0;gap:20px;padding:19px 0 22px}.tabs{padding:4px;background:#e8edef;border-radius:10px}.tabs button{font-size:12px;font-weight:500;padding:10px 14px;min-height:42px;border-radius:7px}.tabs button.active{background:#fff;box-shadow:0 1px 4px #24453414}.filters{gap:10px;min-width:340px}.filters label>span{font-size:10px;margin-bottom:5px;color:#61737c}.filters select{border:1px solid #d3dfe3;border-radius:8px;background:#fff;font-size:12px;padding:9px 26px 9px 10px;min-height:42px;max-width:none}.filters label{min-width:0}#practiceContext{display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid var(--line);padding:0 0 17px;font-size:12px;color:var(--muted)}#practiceContext .text-link{font-size:13px}.study-panel{border-radius:15px;padding:26px;border-color:var(--line)}.study-panel h2{font:600 25px/1.3 Golos,Arial,sans-serif;letter-spacing:-.65px}.study-panel p{line-height:1.8}.study-catalog{gap:17px}.study-catalog h2{font-size:23px}.study-catalog>.study-panel:hover{border-color:#8cbaaf}.study-stat{border-color:var(--line);border-radius:14px}.study-stat strong{font:600 38px/1.2 Golos,Arial,sans-serif;letter-spacing:-1.4px;font-variant-numeric:tabular-nums}.study-stat span{font-size:12px}.study-list>button{min-height:62px}.study-list>button:hover{background:#eef5f2}.study-message{background:#eaf4f0;color:#426c61;padding:16px 18px}.study-form-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.study-check{font-size:13px;min-height:48px;padding:12px;border-radius:9px;background:#fbfcfc}.study-check:has(input:checked){border-color:#88c5b5;background:#edf7f2}.study-question-map button{min-width:40px;min-height:40px}.number-grid button{border-radius:8px}.number-grid button.current{border-color:var(--green)}.study-toolbar{font-size:13px}.study-table{line-height:1.65}.error-map h2{font-size:15px}.error-count{font:600 33px Golos,Arial,sans-serif}.compare-grid .task-card h2{font-size:21px}.chain-strip{gap:8px}.chain-strip .arrow{min-width:30px}.chain-card .chain-strip img{height:46px}.empty h2{font:600 26px/1.3 Golos,Arial,sans-serif;letter-spacing:-.7px}.empty{padding:42px 25px;border-radius:16px}.empty p{line-height:1.8}.theory-rules p{font-size:14px;line-height:1.8}.theory-rules strong{font-weight:600}.theory-example summary{font-size:14px}dialog{font-family:Golos,Arial,sans-serif;border-radius:18px;padding:28px;border-color:#d8e2e4}dialog h2,.dialog-head h2{font-family:Golos,Arial,sans-serif;font-size:25px;font-weight:600;line-height:1.3;letter-spacing:-.6px}.close{flex:0 0 36px;background:#edf2f3}.dialog-copy,dialog p,dialog li{line-height:1.8}.dialog-actions .subtle,.dialog-actions .primary{min-width:100px}#toast{border-radius:10px;line-height:1.5;background:#183c35;font-size:13px;z-index:30}footer{font-size:11px;margin-top:36px;padding:24px 0 28px;border-color:var(--line);align-items:center}footer button{font-size:11px;color:var(--muted);min-height:32px}#footerCount{color:var(--muted)}.catalog-note{font-size:12px;line-height:1.75;margin-top:20px}
/* A reader with an explicit table of contents and independently saved progress. */
.reader-toolbar{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:14px 0 22px}.reader-toolbar .text-link{font-size:13px}.reader-layout{display:grid;grid-template-columns:250px minmax(0,1fr);gap:36px;align-items:start}.reader-toc{position:sticky;top:20px;padding:15px 0}.reader-toc h2{font-size:14px;font-weight:600;letter-spacing:0;margin:0 0 17px}.reader-toc nav{display:flex;flex-direction:column;gap:5px}.reader-toc nav>a{display:flex;align-items:flex-start;gap:11px;font-size:12px;line-height:1.55;padding:11px 12px;border-radius:9px;color:#63747c}.reader-toc nav>a:hover{background:#edf2f3;color:var(--ink)}.reader-toc nav>a.active{background:#e1f1eb;color:#075f54;font-weight:550}.toc-number{font-size:11px;flex:0 0 20px;padding-top:1px;color:#7f9299}.toc-number .ui-icon{height:16px;width:16px;flex-basis:16px}.reader-toc nav>a:last-child>.ui-icon{width:17px;height:17px;flex-basis:17px;margin-top:2px}.reader-toc 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