:root{--ink:#243a33;--muted:#69766e;--accent:#146b58;--accent-soft:#e5eee4;--line:#dfe3d8;--paper:#fffefa;--canvas:#f7f7f0;--peach:#f0b694;--gold:#ddad57;--radius:22px;--shadow:0 12px 32px #263c3210}

*{box-sizing:border-box}
[hidden]{display:none!important}
html{scroll-behavior:smooth;scroll-padding-top:30px}
body{margin:0;background:var(--canvas);color:var(--ink);font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif;font-size:15px;line-height:1.65}
button,input{font:inherit}
button{cursor:pointer}
button:disabled{cursor:wait;opacity:.65}
button:focus-visible,a:focus-visible,input:focus-visible,[tabindex]:focus-visible{outline:3px solid #bd6939;outline-offset:4px}
button{transition:background .15s,transform .15s,box-shadow .15s}
button:not(:disabled):active{transform:translateY(1px)}
input{color:var(--ink)}
.shell{max-width:1220px;padding:0 40px;margin:auto}
.skip-link{position:fixed;left:20px;top:12px;opacity:0;pointer-events:none;z-index:20;background:var(--ink);color:white;padding:12px 18px;border-radius:12px}
.skip-link:focus{opacity:1;pointer-events:auto}
.topbar{min-height:100px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:24px}
.brand-home{border:0;background:none;display:flex;align-items:center;gap:12px;padding:0;text-align:left;color:var(--ink)}
.brand-mark{display:grid;grid-template-columns:repeat(2,16px);gap:3px;transform:rotate(-8deg)}
.brand-mark i{width:16px;height:16px;background:var(--accent);border-radius:4px}
.brand-mark i:nth-child(2){border-radius:50%;background:var(--peach)}
.brand-mark i:nth-child(3){background:var(--gold);border-radius:50% 4px 4px 4px}
.brand{font-weight:850;font-size:20px;letter-spacing:1px;line-height:1.2}
.brand-sub{display:block;font-size:8px;letter-spacing:1.8px;color:var(--muted);font-weight:600;margin-top:7px}
.main-nav{display:flex;align-items:center;gap:30px}
.nav-link{border:0;background:none;color:var(--muted);padding:14px 0;font-size:14px;font-weight:700;position:relative}
.nav-link.selected{color:var(--accent)}
.nav-link.selected:after{content:"";position:absolute;bottom:3px;height:3px;border-radius:3px;left:10%;right:10%;background:var(--accent)}
.count-badge{display:inline-grid;place-items:center;min-width:20px;height:20px;font-size:11px;border-radius:50%;background:#e8ebe1;margin-left:4px}
.mode-label{font-size:11px;padding:5px 10px;border:1px solid var(--line);border-radius:30px;color:var(--muted)}
.hero-intro{display:grid;grid-template-columns:1.15fr 1fr;gap:64px;align-items:center;padding:62px 0 46px}
.eyebrow,.progress-kicker,.section-number{font-size:11px;font-weight:750;letter-spacing:1.2px;color:var(--muted)}
.eyebrow{margin:0 0 16px}
.tiny-star{font-size:18px;color:#b17342;vertical-align:middle;margin-right:5px}
.hero-copy h1{font-size:clamp(34px,4.5vw,55px);font-weight:850;letter-spacing:-2px;line-height:1.34;margin:16px 0 22px}
.title-accent{color:var(--accent);position:relative;white-space:nowrap}
.title-accent:after{content:"";height:8px;background:#dfe8c9;position:absolute;bottom:0;left:0;right:0;z-index:-1;transform:rotate(-2deg)}
.subtitle{font-size:16px;line-height:1.9;color:var(--muted);margin:0 0 24px}
.learning-promise{display:flex;align-items:center;gap:13px;font-size:11px;color:var(--muted);margin-top:30px}
.learning-promise span{white-space:nowrap}
.learning-promise b{color:var(--accent);font-size:10px;margin-right:5px}
.learning-promise i{font-style:normal;color:#b3bcae}
.recommendation-panel{background:#e7eddf;border-radius:26px;overflow:hidden;border:1px solid #dce4d1;box-shadow:var(--shadow);position:relative}
.feature-art{height:151px;position:relative;overflow:hidden;background:linear-gradient(120deg,#ebefdf,#dce7d7)}
.art-bars{position:absolute;display:flex;align-items:flex-end;gap:10px;left:65px;top:23px;transform:rotate(-8deg)}
.art-bars i{width:32px;height:75px;background:#579078;border-radius:8px 8px 4px 4px;box-shadow:7px 7px 0 #146b5814}
.art-bars i:nth-child(2){height:100px;background:#146b58}
.art-bars i:nth-child(3){height:52px;background:var(--peach)}
.art-bars i:nth-child(4){height:85px;background:#d3af63}
.art-bars i:nth-child(5){height:38px;background:#acc6a0}
.art-orbit{position:absolute;width:170px;height:170px;border:1px solid #899f7944;border-radius:50%;top:-74px;right:-24px}
.art-dot{position:absolute;width:17px;height:17px;background:var(--paper);border-radius:50%;left:26px;top:38px}
.art-note{position:absolute;right:16px;bottom:17px;font-size:10px;letter-spacing:2px;color:#668268;writing-mode:vertical-rl}
.feature-copy{padding:22px 26px 26px;background:#f0f3e8}
.feature-copy .progress-kicker{color:var(--accent)}
.feature-copy h2{font-size:23px;line-height:1.4;margin:8px 0}
.feature-copy p{font-size:12px;color:var(--muted);margin:0 0 20px;min-height:20px}
.primary,.secondary,.ghost,.text-button{border:0;border-radius:11px;padding:12px 18px;font-weight:700;font-size:13px;line-height:1.55}
.primary{background:var(--accent);color:white;display:inline-flex;align-items:center;justify-content:center;gap:22px;box-shadow:0 4px 9px #146b5814}
.primary:not(:disabled):hover{background:#0a5645;box-shadow:0 5px 14px #146b5826}
.secondary{background:#e4eadf;color:var(--ink)}
.secondary:not(:disabled):hover{background:#d6e2ce}
.ghost{background:transparent;border:1px solid #cdd7c8;color:var(--ink)}
.text-button{background:transparent;color:var(--accent);padding:9px 5px}
.text-button:not(:disabled):hover{text-decoration:underline;text-underline-offset:4px}
.welcome-loading{min-height:310px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:20px;color:var(--muted);border:1px dashed var(--line);border-radius:26px}
.loading-shape{width:36px;height:36px;background:#dbe5d1;border-radius:10px;transform:rotate(-10deg)}
.active-session-banner{display:flex;gap:18px;align-items:center;background:#e8eee0;padding:24px;border-radius:18px;border:1px solid #d7e1ce;margin-bottom:24px}
.resume-icon{width:42px;height:42px;flex:none;display:grid;place-items:center;border-radius:50%;background:var(--paper);color:var(--accent);font-size:22px}
.active-copy{flex:1}
.active-copy strong{display:block;margin:3px 0;font-size:17px}
.active-copy p{font-size:12px;margin:4px 0}
.active-actions{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.progress-strip{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:18px 0 24px;border-bottom:1px solid var(--line);margin-bottom:32px}
.progress-strip strong{display:block;font-size:14px;margin-top:4px}
.recent-units{display:flex;gap:6px;flex-wrap:wrap;justify-content:flex-end}
.recent-unit{font-size:10px;padding:4px 8px;border-radius:6px;background:#e9ece3;color:var(--muted)}
.recent-unit.completed{background:#e0eddf;color:var(--accent)}
.catalog{padding:16px 0 30px}
.catalog-heading{display:flex;justify-content:space-between;gap:20px;align-items:end;margin:0 0 24px}
.catalog-heading h2{font-size:25px;letter-spacing:-.5px;margin:0}
.catalog-heading .eyebrow{margin-bottom:6px}
.catalog-heading>p{font-size:12px;color:var(--muted);margin:0 0 4px}
.theme-filters{display:flex;gap:8px;flex-wrap:wrap;margin:0 0 30px}
.filter-chip{padding:9px 17px;border:1px solid var(--line);border-radius:30px;background:transparent;color:var(--muted);font-size:12px}
.filter-chip.selected{background:var(--ink);color:white;border-color:var(--ink)}
.theme-group{margin-bottom:30px}
.theme-heading{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:14px}
.theme-heading h3{font-size:14px;margin:0}
.theme-heading>span{font-size:11px;color:var(--muted)}
.theme-unit-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.unit-card{position:relative;display:flex;flex-direction:column;align-items:flex-start;text-align:left;min-height:225px;padding:23px;background:var(--paper);border:1px solid var(--line);border-radius:18px;color:var(--ink);transition:border-color .2s,box-shadow .2s,transform .2s}
.unit-card:hover{border-color:#6f9e87;box-shadow:var(--shadow);transform:translateY(-3px)}
.unit-card.recommended{border-color:#96b99c}
.unit-card.active-unit{background:#f0f5e8;border-color:#7ca67d}
.unit-symbol{width:42px;height:42px;display:grid;place-items:center;border-radius:12px;background:#e8eee1;color:var(--accent);font-size:24px;line-height:1;margin-bottom:18px;font-weight:400}
.theme-group[data-theme="uncertainty-evidence"] .unit-symbol{background:#f9e6d9;color:#b26c43}
.theme-group[data-theme="logic-structure"] .unit-symbol{background:#e8e6f3;color:#766197}
.theme-group[data-theme="systems-space"] .unit-symbol{background:#e4eaf0;color:#4b788e}
.unit-category{font-size:10px;color:var(--muted);margin-bottom:7px;letter-spacing:.6px}
.unit-mode{display:none}
.unit-card strong{font-size:17px;line-height:1.45;margin:0 0 8px}
.unit-subtitle{font-size:12px;color:var(--muted);line-height:1.7;margin-bottom:18px}
.unit-cta{font-size:11px;font-weight:700;color:var(--accent);margin-top:auto}
.recommend-badge{position:absolute;top:23px;right:20px;font-size:10px;padding:3px 8px;border-radius:20px;background:#edf2e7;color:var(--accent)}
.message{font-size:13px;line-height:1.7;overflow-wrap:anywhere}
.message:not(:empty){padding:12px 15px;background:#f5ead6;color:#6f512a;border-radius:10px;margin:15px 0}
.muted{color:var(--muted)}
.learning{padding:25px 0 50px}
.session-actions{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:24px}
.session-actions>div{display:flex;gap:15px}
.session-actions button{font-size:12px}
.learning-header{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:13px}
.stage-label{font-size:20px;font-weight:800}
.stage-guidance{font-size:12px;color:var(--muted);margin:3px 0}
.journey{display:flex;gap:22px;list-style:none;margin:0;padding:0}
.journey li{font-size:11px;font-weight:650;color:#8a958c}
.journey li.current{color:var(--accent)}
.journey li span{margin-left:4px}
.progress{height:3px;background:#e5e8dd;margin:0 0 25px;border-radius:5px;overflow:hidden}
.progress span{display:block;height:100%;width:16%;background:var(--accent);transition:width .2s}
.workspace{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:22px;align-items:start}
.card{background:var(--paper);border:1px solid var(--line);border-radius:var(--radius);padding:28px;box-shadow:0 8px 24px #253b3105}
.challenge-title-row{display:flex;justify-content:space-between;gap:12px}
.save-status{font-size:10px;color:var(--muted);text-align:right}
.card h2{font-size:24px;line-height:1.45;letter-spacing:-.3px;margin:14px 0 22px}
.task-goal-block{background:#eef2e7;border-radius:12px;padding:15px 18px;margin-bottom:20px}
.task-kicker{font-size:10px;font-weight:700;letter-spacing:.6px;color:var(--muted)}
.task-goal-block p{margin:5px 0 0;font-size:14px;font-weight:650;line-height:1.8}
.problem{font-size:17px;line-height:1.95;white-space:pre-wrap;margin-top:7px;overflow-wrap:anywhere}
.interaction-host{margin:25px 0 0;padding:21px;background:#f4f5ed;border:1px solid #e5e8dc;border-radius:16px;scroll-margin-top:25px}
.exploration-kicker{font-size:11px;font-weight:750;letter-spacing:1px;color:var(--accent)}
.exploration-heading p{font-size:13px;margin:6px 0 18px;color:#57685b;line-height:1.75}
.scene-instruction,.scene-target{font-size:12px;line-height:1.75;margin:10px 0}
.variant-tabs,.operation-row,.structure-steps,.pattern-rules,.sampling-options,.network-routes,.constraint-controls{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:15px}
.explore-scene button{font-size:11px;padding:9px 12px}
.explore-scene button.selected,.explore-scene button[aria-pressed="true"]{background:var(--accent);color:white;border-color:var(--accent)}
.explore-scene button.selected:not(:disabled):hover{background:#0f5949;color:white}
.selection-status,.operation-result,.counterexample-readout,.structure-detail{font-size:12px;line-height:1.8;margin:16px 0 0;padding:11px 13px;background:#fffdf8;border-radius:10px;color:#5c6a5f}
.weight-bars{display:grid;gap:13px;margin:18px 0}
.weight-row{display:grid;grid-template-columns:100px 1fr;gap:12px;align-items:center}
.weight-label{font-size:10px;display:flex;flex-wrap:wrap;gap:3px 7px}
.weight-label strong{width:100%;font-size:12px}
.weight-track{height:42px;background:#e3e7d8;border-radius:7px;overflow:hidden}
.weight-fill{height:100%;display:flex;align-items:center;padding:0 10px;background:#6c9c7b;color:#fff;font-size:11px;min-width:65px;transition:width .3s}
.weight-row:nth-child(2) .weight-fill{background:#b98561}
.quantity-row{display:flex;gap:12px}
.quantity-card,.target-unit-card{padding:15px;border:1px solid #dce4d5;border-radius:12px;background:var(--paper);flex:1;min-width:0}
.quantity-label{display:block;font-size:10px;color:var(--muted)}
.quantity-value{font-size:28px;line-height:1.5;display:inline-block;margin:5px 6px 5px 0}
.quantity-unit{font-size:11px}
.target-unit-card{margin:12px 0;display:flex;align-items:center;justify-content:space-between;gap:10px;background:#e3ebdc}
.target-unit{font-size:16px}
.atom-strip{display:grid;grid-template-columns:repeat(6,1fr);gap:8px;margin:16px 0}
.atom-chip{border:1px solid #b9cdb5;border-radius:50%;aspect-ratio:1;background:#edf1e4;color:var(--accent);font-size:20px!important;font-weight:800;padding:0!important}
.arrow-compare{display:grid;gap:8px}
.arrow-card{border:1px solid #cfd9c6;background:white;color:var(--ink);border-radius:11px;padding:12px;text-align:left;flex:1}
.counterexample-row{display:flex;gap:8px;margin-top:12px}
.number-chip{border:1px solid #cdd8c7;border-radius:9px;background:white;color:var(--ink);min-width:42px;min-height:40px}
.explore-badge{display:inline-block;background:#e6ebdf;border-radius:5px;padding:3px 7px;margin:3px;font-size:11px}
.explore-badge.yes{color:#2b7156}
.explore-badge.no{color:#9c6046}
.boundary-grid{display:grid;grid-template-columns:repeat(var(--grid-w,10),1fr);gap:3px;max-width:285px;margin:18px auto;aspect-ratio:1}
.grid-cell{background:#78a188;border:1px solid #6d947c;border-radius:2px}
.grid-cell.removed{background:transparent;border:1px dashed #b4c3ad}
.structure-step{flex:1;border:1px solid var(--line);background:white;border-radius:8px;min-width:90px}
.water-parts{display:grid;gap:8px;margin:16px 0}
.water-row{padding:12px;border:2px solid transparent;border-radius:12px;background:#f4f5ee}
.water-row.selected{border-color:#91b09f;background:#edf4ed}
.water-row-label{display:block;font-size:12px;margin-bottom:8px}
.water-row-cells{display:grid;grid-template-columns:repeat(12,1fr);gap:4px;height:38px}
.water-part{background:#e1e9df;border-radius:4px}
.water-part.filled{background:#5d9f94}
.digit-row{display:flex;flex-wrap:wrap;gap:6px}
.constraint-display{font-size:28px;letter-spacing:10px;font-weight:750;padding:20px;background:white;border:1px solid var(--line);border-radius:12px;text-align:center;margin:15px 0}
.answer-box{margin-top:27px;padding-top:23px;border-top:1px solid var(--line)}
.response-prompt{font-size:13px;margin:10px 0 15px;color:#52665a}
.answer-box label{font-size:11px;display:block;font-weight:700;color:var(--muted);margin:0 0 8px}
.answer-row{display:flex;align-items:center;gap:10px}
.answer-row input{min-width:0;flex:1;width:100%;border:1px solid #bcc9b7;background:white;border-radius:10px;font-size:18px;padding:11px 12px;line-height:1.5}
.answer-row .unit{font-size:12px;white-space:nowrap}
.answer-row .primary{font-size:12px;padding:14px;gap:12px;white-space:nowrap}
.choice-box{display:grid;gap:9px}
.choice-option{border:1px solid var(--line);background:#fafbf5;border-radius:12px;padding:13px 15px;text-align:left;color:var(--ink);font-size:13px}
.choice-option:before{content:"";display:inline-block;width:12px;height:12px;border:1px solid #9dad9e;border-radius:50%;margin-right:9px;vertical-align:middle}
.choice-option.selected{background:#e7f0e1;border-color:#739a76}
.choice-option.selected:before{background:var(--accent);box-shadow:inset 0 0 0 3px #e7f0e1}
.choice-submit{justify-self:start;margin-top:5px}
.help-entry{margin-top:18px;display:flex;align-items:center;justify-content:space-between;gap:12px;font-size:11px;color:var(--muted)}
.help-entry button{font-size:12px}
.support-sidebar{position:sticky;top:24px}
.thinking-guide{background:#f0efe2;box-shadow:none}
.guide-spark{font-size:36px;line-height:1;color:#ab7b45;display:block;margin-bottom:18px}
.thinking-guide h3{font-size:17px;margin:5px 0 14px}
.thinking-guide ul{padding-left:18px;font-size:13px;line-height:2.3}
.thinking-guide .muted{font-size:11px;margin:24px 0 0}
.soft{background:#eaf0e3;border-color:#d6e1cd;padding:23px}
.hint-status-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap;font-size:10px}
.hint-progress{color:white;padding:3px 8px;background:var(--accent);border-radius:6px;white-space:nowrap}
.hint-level-label{color:var(--muted)}
.hint{font-size:15px;line-height:1.9;margin:18px 0}
.hint-action{background:#fafff2;border-radius:12px;padding:15px;font-size:12px;line-height:1.8}
.hint-action>span{font-weight:800;font-size:10px;letter-spacing:1px}
.hint-action p{margin:7px 0}
.hint-action .text-button{font-size:11px;padding:3px 0}
.hint-exhausted{font-size:11px;line-height:1.7;color:#6b7157;padding:10px 0 0}
.button-row{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}
.soft .button-row{flex-direction:column;align-items:stretch;gap:8px}
.soft button{font-size:11px}
.soft #more-hint:disabled{opacity:1;cursor:default;background:#dbe5d2;color:#62715e}
.diagnosis{border-top:1px solid #cbd8c2;padding-top:15px;margin-top:15px;font-size:12px;line-height:1.8}
.diagnosis .muted{font-size:11px}
.warm{grid-column:1/-1;background:#f8edd9;max-width:750px;margin:auto;padding:38px}
.explain{font-size:17px;line-height:1.9}
.thought{padding:20px;background:#fff9ed;border-radius:14px;margin:22px 0}
.thought span{font-size:11px;font-weight:800;color:#997242}
.thought p{margin:8px 0 0}
.summary{grid-column:1/-1;background:#eef2e7;text-align:center;max-width:790px;margin:auto;width:100%;padding:45px}
.summary-symbol{display:block;font-size:62px;line-height:1.3;color:var(--accent)}
.summary h2{font-size:31px;margin:8px 0 20px}
.summary #summary-idea{font-size:17px;line-height:1.8;max-width:590px;margin:auto}
.summary .eyebrow{margin-top:14px}
.steps{display:flex;gap:8px;flex-wrap:wrap;justify-content:center;margin:24px 0}
.steps span{font-size:11px;padding:5px 9px;border-radius:8px;background:#dfe9d6}
.summary blockquote{margin:22px auto;padding:22px;border-radius:14px;background:var(--paper);font-size:17px;line-height:1.8;border-left:3px solid var(--gold);text-align:left}
.summary-note{font-size:12px;color:var(--muted)}
.summary .button-row{justify-content:center}
.notebook{padding:60px 0 80px}
.notebook h1{font-size:40px;line-height:1.4;letter-spacing:-1px;margin:0 0 20px}
.review-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;margin-top:35px}
.review-card{background:var(--paper);border:1px solid var(--line);border-radius:18px;padding:26px}
.review-card h2{font-size:20px;margin:10px 0}
.review-card>p{font-size:14px;line-height:1.9}
.review-card blockquote{margin:20px 0;padding-left:14px;border-left:2px solid var(--gold);font-size:14px;color:var(--muted)}
.review-card .steps{justify-content:flex-start}
.review-date{font-size:10px;color:var(--muted)}
.notebook-empty{padding:50px 25px;text-align:center;border:1px dashed #ccd6c2;border-radius:22px;margin-top:35px}
.notebook-empty>span{color:#9fac88;font-size:45px}
.notebook-empty h2{font-size:22px}
.notebook-empty p{color:var(--muted);font-size:14px}
.switch-dialog{position:fixed;inset:0;background:#14291fd0;z-index:10;display:grid;place-items:center;padding:20px;overflow:auto}
.switch-dialog-card{max-width:470px;width:100%;background:var(--paper);border-radius:24px;padding:34px;box-shadow:0 20px 70px #12251f66}
.switch-dialog-card h2{font-size:24px;line-height:1.4;margin:10px 0 20px}
.switch-dialog-card p{font-size:14px;line-height:1.85}
.switch-actions{display:flex;flex-direction:column;gap:10px;margin-top:25px}
footer{border-top:1px solid var(--line);padding:25px 0 35px;display:flex;align-items:center;justify-content:space-between;gap:22px;font-size:10px;color:var(--muted)}
footer>div{display:flex;gap:17px;align-items:center}
.footer-brand{font-size:13px;font-weight:750;color:var(--ink)}
footer p{margin:0;text-align:right;max-width:340px}
noscript{padding:30px;text-align:center}

@media(min-width:1350px){.shell{padding:0 25px}
}
@media(max-width:1000px){.shell{padding:0 25px}
.hero-intro{gap:30px}
.workspace{grid-template-columns:minmax(0,1fr) 255px;gap:15px}
.card{padding:22px}
.hero-copy h1{font-size:43px}
.learning-promise{gap:8px;font-size:10px}
.active-session-banner{flex-wrap:wrap}
.active-actions{width:100%;padding-left:60px}
.theme-unit-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
.answer-row{flex-wrap:wrap}
.answer-row input{flex-basis:65%}
.answer-row .primary{margin-top:4px}
.journey{gap:12px}
}
@media(max-width:760px){.shell{padding:0 20px}
.topbar{min-height:83px;gap:12px}
.brand{font-size:17px}
.brand-sub{font-size:6px;letter-spacing:1.3px}
.brand-mark{grid-template-columns:repeat(2,13px);gap:2px}
.brand-mark i{width:13px;height:13px}
.brand-home{gap:9px}
.main-nav{gap:16px}
.nav-link{font-size:12px}
.mode-label{display:none}
.count-badge{font-size:9px;min-width:16px;height:16px;margin-left:2px}
.hero-intro{grid-template-columns:1fr;padding:38px 0 28px;gap:30px}
.hero-copy h1{font-size:38px;letter-spacing:-1px;margin:10px 0 18px}
.hero-copy .eyebrow{font-size:10px}
.subtitle{font-size:14px;margin-bottom:20px}
.learning-promise{margin-top:22px;font-size:11px;gap:12px}
.feature-art{height:118px}
.art-bars{top:0;left:65px}
.feature-copy{padding:20px 23px}
.feature-copy h2{font-size:22px}
.feature-copy p{margin-bottom:16px}
.recommendation-panel{border-radius:21px}
.welcome-loading{min-height:180px}
.active-session-banner{padding:18px;gap:12px}
.active-copy{flex-basis:75%}
.active-copy strong{font-size:16px}
.active-actions{padding:0;gap:8px}
.active-actions button{font-size:11px;padding:11px}
.catalog-heading{display:block;margin-bottom:20px}
.catalog-heading h2{font-size:22px}
.catalog-heading>p{font-size:11px;margin-top:9px}
.catalog{padding-top:16px}
.theme-filters{gap:7px;margin-bottom:23px}
.filter-chip{font-size:11px;padding:8px 12px}
.theme-unit-grid{grid-template-columns:1fr;gap:12px}
.unit-card{min-height:190px;padding:22px 22px 22px 86px}
.unit-symbol{position:absolute;left:21px;top:24px;width:45px;height:45px}
.unit-card strong{font-size:18px}
.unit-category{margin-top:33px}
.unit-subtitle{font-size:12px;line-height:1.8}
.recommend-badge{top:22px;right:18px}
.theme-heading h3{font-size:13px}
.progress-strip{display:block}
.recent-units{justify-content:flex-start;margin-top:12px}
.progress-strip strong{font-size:13px}
.learning{padding-top:15px}
.session-actions{gap:8px;margin-bottom:20px}
.session-actions>div{gap:7px;flex-wrap:wrap;justify-content:flex-end}
.session-actions button{font-size:10px;padding:5px 0}
.session-actions #restart-active{display:none}
.learning-header{display:block}
.stage-label{font-size:20px}
.journey{margin-top:16px;justify-content:space-between}
.journey li{font-size:10px}
.progress{margin-top:16px;margin-bottom:20px}
.workspace{grid-template-columns:1fr;gap:16px}
.card{padding:22px 18px;border-radius:18px}
.card h2{font-size:22px;margin:12px 0 20px}
.section-number{font-size:10px}
.save-status{font-size:9px}
.problem{font-size:16px;line-height:1.95}
.task-goal-block{padding:13px}
.task-goal-block p{font-size:13px}
.interaction-host{padding:16px 12px;margin-top:20px}
.exploration-heading p{font-size:12px}
.weight-row{grid-template-columns:83px 1fr;gap:8px}
.weight-fill{font-size:10px;padding:0 7px}
.atom-strip{gap:6px}
.quantity-card{padding:11px}
.quantity-value{font-size:24px}
.quantity-unit{font-size:10px}
.quantity-row{gap:8px}
.answer-row input{flex-basis:70%}
.answer-row .primary{width:100%;margin-top:6px;padding:13px}
.help-entry{gap:8px;font-size:10px}
.help-entry button{font-size:11px}
.support-sidebar{position:static}
.thinking-guide{display:none}
.hint{font-size:16px}
.soft .button-row{flex-direction:row}
.soft .button-row>button{flex:1;min-width:120px}
.hint-status-row{font-size:11px}
.hint-action{font-size:13px}
.soft button{font-size:12px}
.diagnosis-actions{flex-direction:column!important}
.soft #show-diagnosis{flex-basis:100%}
.warm{padding:26px 22px}
.summary{padding:30px 22px}
.summary h2{font-size:25px}
.summary #summary-idea,.summary blockquote{font-size:15px}
.summary .button-row{flex-direction:column}
.notebook{padding-top:36px}
.notebook h1{font-size:32px}
.review-list{grid-template-columns:1fr;margin-top:25px}
.review-card{padding:23px}
.switch-dialog-card{padding:26px}
.switch-dialog-card h2{font-size:22px}
footer{display:block;padding-top:23px}
footer>div{justify-content:space-between}
footer p{text-align:left;margin-top:12px;font-size:9px;max-width:none}
}

@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}
*,*:before,*:after{transition:none!important;animation:none!important}
}


.connection-banner{display:flex;align-items:center;justify-content:space-between;gap:15px;background:#f9e8cb;border:1px solid #e4cba3;border-radius:12px;padding:14px 18px;margin-top:18px;font-size:12px}
.connection-banner button{flex:none}
@media(max-width:760px){.connection-banner{align-items:stretch;flex-direction:column}
}

@media(max-width:420px){
.primary,.secondary,.ghost{min-height:44px}
.active-actions button,.recommendation-panel button{width:100%}
.filter-chip{min-height:40px}
.explore-scene button{min-height:44px}
}

/* Concrete mathematical objects, with labels readable at narrow widths. */
.pattern-sequence{display:flex;flex-wrap:wrap;gap:10px;margin:24px 0;align-items:center}
.pattern-chip{display:grid;place-items:center;min-width:48px;height:58px;border-radius:12px;background:#fff;border:1px solid var(--line);font-size:25px;font-weight:700}
.pattern-chip.continuation{background:#e0ebe1;border:2px dashed #628572;color:var(--accent)}
.coverage-diagram{display:grid;grid-template-columns:repeat(6,1fr);gap:12px;max-width:390px;padding:22px;background:#fff;border-radius:16px;margin:20px auto}
.school-person{font-size:30px;text-align:center;line-height:1;color:#ddd9d0}
.school-person.has-opportunity{color:#397964;text-shadow:0 7px 0 #a9c6b7}
.coverage-caption{font-size:12px;line-height:1.8;color:var(--muted);text-align:center}
.network-diagram{margin:20px 0;background:#fff;border-radius:16px;overflow:hidden}
.network-diagram svg{display:block;width:100%;height:auto;min-height:115px}
.network-edge{stroke:#91ac9e;stroke-width:5}
.network-weight{font-size:22px;fill:#735131;font-weight:700}
.network-node{fill:#e1ece3;stroke:#487a64;stroke-width:2}
.network-node-label{font-size:18px;fill:#234d3c;font-weight:700}
.state-operations{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}
.bucket-comparison{display:flex;align-items:center;justify-content:center;gap:16px;margin:24px 0}
.bucket-state{display:grid;grid-template-columns:repeat(2,minmax(52px,70px));gap:12px;align-items:end}
.bucket-state-label{grid-column:1/-1;font-size:12px;text-align:center}
.bucket-vessel{position:relative;height:104px;border:2px solid #6f9489;border-top:0;border-radius:0 0 12px 12px;overflow:hidden;background:#fff}
.bucket-water{position:absolute;bottom:0;left:0;right:0;background:#acd4e4;border-top:2px solid #5799b3;transition:height .2s ease}
.bucket-water.empty{border:0}
.bucket-reading{position:absolute;inset:0;display:grid;place-items:center;font-weight:700;font-size:13px;color:#1b4759}
.state-arrow{color:#628572;font-size:25px}
.constraint-number{display:flex;align-items:center;justify-content:center;gap:10px;font-size:43px;font-weight:700;letter-spacing:8px;padding:20px 0;color:#365947}
.chosen-digit{display:inline-grid;place-items:center;background:#fff;border:2px solid #9ab9a6;border-radius:12px;min-width:54px;height:64px;letter-spacing:0}
.constraint-sum{text-align:center;font-size:15px;font-weight:600;margin:0 0 20px}
@media(max-width:420px){
.pattern-sequence{gap:6px}.pattern-chip{min-width:38px;height:48px;font-size:21px}
.bucket-comparison{gap:8px}.bucket-state{grid-template-columns:repeat(2,48px);gap:6px}.bucket-vessel{height:92px}.state-arrow{font-size:20px}
.coverage-diagram{gap:8px;padding:18px}.school-person{font-size:25px}
}
@media(prefers-reduced-motion:reduce){.bucket-water{transition:none}}
.network-path-card{padding:14px;border:2px solid transparent;border-radius:14px;margin:8px;background:#fafaf6;transition:background .15s}
.network-path-card.selected{border-color:#91b19d;background:#edf4ed}
.network-path-title{font-size:13px;font-weight:700;color:#365947}