:root{color-scheme:light;--paper:#f6f3ec;--ink:#252b34;--muted:#666e75;--line:#dcd9d1;--white:#fffdf9;--orange:#a64c30;--blue:#385b78;--mint:#d8e8df;--shadow:0 24px 60px rgba(35,43,52,.08)}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.7 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif}
a{color:inherit;text-decoration:none}
button,input{font:inherit}
button{cursor:pointer}
button:disabled{cursor:default;opacity:.55}
:focus-visible{outline:3px solid var(--orange);outline-offset:3px}
.skip{position:absolute;left:12px;top:-80px;z-index:50;padding:8px 12px;background:#fff}
.skip:focus{top:12px}
.wrap{width:min(1120px,calc(100% - 48px));margin-inline:auto}
.topbar{min-height:80px;padding:15px max(24px,calc((100vw - 1120px)/2));display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}
.brand{font-size:18px;font-weight:750;letter-spacing:-.04em}
.topbar nav{display:flex;gap:30px;color:#505961;font-size:14px}
.topbar nav a:hover,.footer a:hover{color:var(--orange)}
.hero{min-height:650px;display:grid;grid-template-columns:1.1fr .9fr;gap:9%;align-items:center;padding-block:86px 110px}
.eyebrow{margin:0 0 19px;color:var(--orange);font-weight:700;font-size:12px;letter-spacing:.14em;text-transform:uppercase}
h1,h2,h3,p{margin-top:0}
h1,h2{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-weight:700;letter-spacing:-.045em}
h1{font-size:clamp(48px,5.2vw,78px);line-height:1.19;margin-bottom:27px}
h1 em{font-style:normal;color:var(--orange)}
.lead{max-width:560px;color:#4b535b;font-size:20px;line-height:1.85;margin-bottom:34px}
.hero-actions{display:flex;align-items:center;gap:24px;flex-wrap:wrap}
.button{display:inline-flex;align-items:center;gap:20px;justify-content:center;min-height:48px;padding:10px 21px;border-radius:6px;font-weight:700;font-size:14px}
.button.primary{background:var(--ink);color:white}
.button.primary:hover{background:#404a57}
.button.text-button{padding-inline:0;color:var(--blue)}
.hero-visual{height:470px;background:#e9e3d7;border-radius:180px 180px 9px 9px;padding:26px 34px 28px;position:relative;overflow:hidden;box-shadow:var(--shadow)}
.hero-visual::before,.hero-visual::after{content:"";position:absolute;border:1px solid rgba(77,96,112,.16);border-radius:50%;width:510px;height:510px;left:-54px;top:58px}
.hero-visual::after{width:370px;height:370px;left:17px;top:125px}
.visual-top,.visual-bottom{position:relative;z-index:2;display:flex;align-items:center;justify-content:space-between;font-size:12px;font-weight:700;letter-spacing:.08em}
.visual-top{position:absolute;top:45px;left:50%;transform:translateX(-50%);width:180px;justify-content:center;gap:10px}
.visual-dot{width:9px;height:9px;border-radius:50%;background:var(--orange)}
.orbit{width:300px;height:300px;position:absolute;left:50%;top:50%;transform:translate(-50%,-48%);border:1px dashed rgba(37,43,52,.35);border-radius:50%}
.orbit-line{position:absolute;width:225px;height:1px;background:rgba(37,43,52,.28);transform:rotate(-32deg);left:38px;top:145px}
.planet{position:absolute;display:block;border-radius:50%;box-shadow:0 10px 25px rgba(46,60,75,.18)}
.planet-a{width:100px;height:100px;left:-32px;top:110px;background:#bf6247}
.planet-b{width:52px;height:52px;right:7px;top:58px;background:#416178}
.orbit-center{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);width:115px;height:115px;border-radius:50%;background:var(--paper);display:grid;place-content:center;text-align:center;line-height:1.4;font-size:18px;font-weight:750}
.visual-bottom{position:absolute;bottom:28px;left:34px;right:34px;justify-content:center;gap:12px}
.visual-bottom i{width:24px;height:1px;background:var(--ink)}
.research{background:#e8edea;padding-block:100px}
.research-grid{display:grid;grid-template-columns:.8fr 1.2fr;gap:10%}
.section-heading h2{font-size:clamp(33px,3.7vw,52px);line-height:1.28;margin-bottom:24px}
.research-body>p{max-width:690px;font-size:17px;color:#374148;line-height:2;margin-bottom:22px}
.research-body>p a{text-decoration:underline;text-decoration-color:var(--orange);text-underline-offset:4px;color:var(--blue)}
.takeaway{border-top:1px solid #b8cac3;margin-top:32px;padding-top:24px;display:grid;grid-template-columns:120px 1fr;gap:20px}
.takeaway span{color:var(--orange);font-size:13px;font-weight:800;white-space:nowrap}
.takeaway p{margin:0;line-height:1.9}
.library{padding-block:110px}
.library-heading{display:flex;justify-content:space-between;align-items:end;gap:60px}
.section-note{max-width:320px;color:var(--muted);line-height:1.9;margin:0 0 25px}
.tools{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-top:20px;padding-block:20px;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.search-label{display:grid;gap:7px;min-width:270px;max-width:330px;width:100%;font-size:12px;font-weight:700;color:#626a71}
.search-label input{width:100%;height:44px;padding:9px 12px;border:1px solid #c5c6c3;border-radius:5px;background:var(--white);color:var(--ink);font-size:14px}
.filters{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}
.filter{border:1px solid #bec3c2;background:transparent;border-radius:999px;padding:7px 15px;font-size:13px;color:#4a535c}
.filter:hover{border-color:var(--ink)}
.filter[aria-pressed="true"]{background:var(--ink);color:white;border-color:var(--ink)}
.result-count{font-size:13px;color:var(--muted);margin:18px 0 16px}
.cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.lab-card{background:var(--white);border:1px solid #e3e0d8;border-radius:8px;min-height:185px;text-align:left;padding:22px;display:flex;flex-direction:column;transition:transform .16s,box-shadow .16s,border-color .16s}
.lab-card:hover{transform:translateY(-3px);box-shadow:var(--shadow);border-color:#d0c7b8}
.card-meta{font-size:12px;color:var(--orange);font-weight:700;margin-bottom:21px}
.card-title{display:block;font-size:19px;font-weight:750;line-height:1.4;margin-bottom:8px}
.card-description{font-size:13px;line-height:1.7;color:var(--muted)}
.card-arrow{margin-top:auto;align-self:end;color:var(--orange);font-size:21px;line-height:1}
.empty{padding:45px 20px;border:1px dashed #c9c6bd;text-align:center;color:var(--muted);grid-column:1/-1}
.lab-panel{margin-top:30px;background:var(--white);border:1px solid #dedbd3;border-radius:12px;padding:30px;box-shadow:var(--shadow);scroll-margin-top:20px}
.lab-panel[hidden]{display:none}
.lab-top{display:flex;justify-content:space-between;align-items:start;gap:18px;border-bottom:1px solid var(--line);padding-bottom:19px}
.lab-top p{color:var(--orange);font-size:12px;font-weight:750;letter-spacing:.06em;margin:0 0 4px}
.lab-top h3{font-size:28px;line-height:1.35;margin:0}
.close-lab{background:transparent;border:1px solid var(--line);border-radius:5px;padding:7px 12px;font-size:13px;white-space:nowrap}
.lab-description{color:#505861;margin:20px 0}
.lab-layout{display:grid;grid-template-columns:minmax(280px,.82fr) minmax(0,1.18fr);gap:35px}
.level-box{border-radius:7px;background:#f3eee5;padding:17px;margin-bottom:22px}
.level-index{color:var(--orange);font-size:12px;font-weight:800;margin-bottom:5px}
.level-prompt{font-size:17px;font-weight:720;line-height:1.5;margin:0}
.param{display:block;margin-bottom:20px}
.param-head{display:flex;justify-content:space-between;align-items:baseline;gap:10px;margin-bottom:4px}
.param-name{font-size:14px;font-weight:700}
.param-value{font-size:19px;font-weight:800;font-variant-numeric:tabular-nums;color:var(--blue)}
.param input{width:100%;accent-color:var(--orange)}
.param-range{display:flex;justify-content:space-between;color:#59636a;font-size:11px}
.lab-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:21px}
.lab-actions button{border-radius:5px;padding:9px 13px;font-size:13px;font-weight:750}
.check-button,.next-button{border:1px solid var(--ink);background:var(--ink);color:white}
.hint-button,.solution-button{border:1px solid #bfc5c8;background:white;color:var(--ink)}
.hint-text,.feedback{margin:13px 0 0;padding:11px 13px;background:#f4f6f5;border-left:3px solid var(--blue);font-size:13px;line-height:1.75}
.feedback[data-success="true"]{border-color:#54816d;background:#edf4ee}
.feedback[data-success="false"]{border-color:var(--orange);background:#fbf1ea}
.hint-text[hidden],.feedback[hidden],.next-button[hidden],.solution-button[hidden]{display:none}
.result-board{background:#f1f4f2;border:1px solid #e0e7e2;border-radius:8px;padding:18px 20px}
.result-label{display:block;font-size:12px;color:#566a66;font-weight:750}
.result-value{display:block;font-size:34px;font-weight:800;line-height:1.25;font-variant-numeric:tabular-nums;margin:6px 0 14px}
.result-value small{font-size:15px;font-weight:600;margin-left:5px}
.chart{display:block;width:100%;height:auto;background:#fff;border-radius:5px;border:1px solid #d9e2dc}
.chart-caption{font-size:12px;color:#566560;line-height:1.7;margin:9px 0 0}
.scene{display:block;width:100%;height:auto;border-radius:5px;border:1px solid #d9e2dc;background:#fff}
.scene-caption{font-size:12px;color:#566560;line-height:1.7;margin:8px 0 14px}
.param input:disabled{opacity:.35}
.segmented{display:inline-flex;border:1px solid #bfc5c8;border-radius:6px;overflow:hidden;margin-top:4px}
.segmented button{border:0;background:white;padding:7px 16px;font-size:13px;font-weight:700;color:#4a535c}
.segmented button+button{border-left:1px solid #bfc5c8}
.segmented button[aria-pressed="true"]{background:var(--ink);color:white}
.level-steps{list-style:none;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin:0 0 22px;padding:0}
.level-steps button{width:100%;min-height:52px;display:flex;align-items:center;gap:10px;text-align:left;border:1px solid #ddd6ca;border-radius:8px;background:#fbf8f2;padding:8px 11px;color:var(--ink)}
.step-icon{flex:none;width:26px;height:26px;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:800;background:#e4ddd0;color:#5d5a52}
.step-icon svg{width:14px;height:14px}
.step-text{display:grid;min-width:0;line-height:1.35}
.step-title{font-size:13px;font-weight:780;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.step-state{font-size:11px;color:var(--muted)}
.level-steps [data-state="current"]{border-color:var(--orange);background:#fff;box-shadow:0 0 0 1px var(--orange) inset}
.level-steps [data-state="current"] .step-icon{background:var(--orange);color:#fff}
.level-steps [data-state="done"] .step-icon{background:#54816d;color:#fff}
.level-steps [data-state="done"]:hover,.level-steps [data-state="open"]:hover{border-color:#9fb3a8}
.level-steps [data-state="locked"]{cursor:not-allowed;opacity:.62;background:#f1eee8}
.level-steps [data-state="locked"] .step-icon{background:#d6d0c4;color:#6f6a60}
.level-goal{font-size:13px;line-height:1.7;color:#2f5d4a;margin:0 0 9px;padding:7px 10px;background:#e7f0ea;border-radius:5px}
.level-goal[hidden]{display:none}
.goal-tag{display:inline-block;font-size:11px;font-weight:800;letter-spacing:.06em;color:#fff;background:#54816d;border-radius:3px;padding:0 6px;margin-right:7px}
.param-note{margin-left:8px;font-size:11px;font-weight:700;color:var(--orange);background:#fbf1ea;border-radius:3px;padding:1px 6px}
.param-note:empty{display:none}
.run-button{min-width:96px;background:var(--orange)!important;border-color:var(--orange)!important}
.result-pending{font-size:17px;font-weight:700;color:#6b7672}
.feedback .next-button{margin-top:10px;border-radius:5px;padding:9px 16px;font-size:13px;font-weight:750;min-height:36px}
.feedback-body p{margin:0}.feedback-body p+p,.feedback-body p+div{margin-top:7px}
.feedback-title{font-weight:800;font-size:14px}
.feedback[data-success="true"] .feedback-title{color:#2f7d58;font-size:16px}
.feedback[data-success="partial"]{border-color:#c69a2a;background:#fbf6e6}
.why{background:#fff;border:1px solid #cfe2d6;border-radius:6px;padding:9px 11px}
.why-title{font-size:12px;font-weight:800;color:#2f7d58;letter-spacing:.04em}
.hint-text p{margin:0}.hint-text p+p{margin-top:6px}
.toolbox{margin-top:18px;border:1px solid #dde3df;border-radius:6px;background:#f7f9f8;font-size:13px;line-height:1.8;color:#4a5554}
.toolbox summary{cursor:pointer;padding:9px 13px;font-weight:750;color:var(--ink);min-height:40px}
.toolbox summary span{font-weight:500;color:var(--muted);font-size:12px;margin-left:6px}
.toolbox p{margin:0;padding:0 13px 12px}
.tool-tabs{display:flex;gap:4px;padding:0 10px;border-bottom:1px solid #dde3df;overflow-x:auto}
.tool-tabs button{border:0;background:transparent;padding:7px 11px;min-height:36px;font-size:13px;font-weight:750;color:#5d6966;border-bottom:2px solid transparent;white-space:nowrap}
.tool-tabs button[aria-selected="true"]{color:var(--ink);border-bottom-color:var(--orange)}
.tool-panel{padding:12px 0 2px}
.tool-panel[hidden]{display:none}
.tool-panel .chart{margin:0 13px;width:calc(100% - 26px)}
.tool-panel .chart-caption{padding:0 13px 12px}
.formula-list{margin:0;padding:0 13px 10px;display:grid;gap:8px}
.formula-list div{display:grid;grid-template-columns:88px 1fr;gap:8px;align-items:baseline}
.formula-list dt{font-weight:750;color:var(--ink)}
.formula-list dd{margin:0}
.formula-list code{font:600 14px/1.6 "SFMono-Regular",Menlo,Consolas,"PingFang SC",monospace;color:var(--blue);background:#fff;border:1px solid #e0e7e2;border-radius:4px;padding:1px 6px;display:inline-block}
.formula-list small{display:block;color:var(--muted);font-size:12px}
.tool-note{border-top:1px solid #e0e7e2;padding-top:9px!important;margin:0 13px!important;padding-inline:0!important}
.calculator{padding:0 13px 12px}
.calc-label{display:block;font-size:12px;font-weight:700;margin-bottom:4px}
.calc-row{display:flex;gap:6px}
.calc-row input{flex:1;min-width:0;height:38px;border:1px solid #c5ccc8;border-radius:5px;padding:6px 9px;font:15px/1.4 "SFMono-Regular",Menlo,Consolas,monospace;background:#fff}
.calc-equals{min-width:44px;border:1px solid var(--ink);background:var(--ink);color:#fff;border-radius:5px;font-weight:800;font-size:16px}
.calc-keys{display:flex;flex-wrap:wrap;gap:5px;margin-top:7px}
.calc-keys button{min-width:44px;min-height:34px;border:1px solid #cfd6d2;background:#fff;border-radius:5px;font-size:13px}
.calc-output{display:block;min-height:26px;margin-top:6px;font-size:18px;font-weight:800;color:var(--blue);font-variant-numeric:tabular-nums}
.calc-output[data-error="true"]{font-size:13px;font-weight:600;color:var(--orange)}
.calc-note{padding:0!important;font-size:12px;color:var(--muted)}
.lab-top-actions{display:flex;gap:8px}
.tour-button{background:#fbf1ea;border:1px solid #e4c6b7;color:var(--orange);border-radius:5px;padding:7px 12px;font-size:13px;font-weight:750;white-space:nowrap}
.card-badge{margin-left:8px;padding:1px 7px;border-radius:3px;background:#54816d;color:#fff;font-size:11px}
.scene [data-drag]{touch-action:none}
.scene.dragging,.scene.dragging [data-drag]{cursor:grabbing!important}
.lab-panel[data-flagship="true"] .result-board{position:sticky;top:12px;align-self:start}
.tour-layer{position:fixed;inset:0;z-index:60;pointer-events:none}
.tour-backdrop{position:fixed;inset:0;background:rgba(24,30,36,.46);pointer-events:auto}
.tour-card{position:fixed;right:24px;bottom:24px;width:min(390px,calc(100vw - 32px));background:var(--white);border-radius:10px;padding:18px 20px 16px;box-shadow:0 22px 60px rgba(0,0,0,.28);pointer-events:auto}
.tour-count{margin:0 0 3px;color:var(--orange);font-size:12px;font-weight:800;letter-spacing:.06em}
.tour-card h4{margin:0 0 6px;font-size:19px;line-height:1.4}
.tour-card #tour-body{margin:0;font-size:14px;line-height:1.8;color:#434c54}
.tour-dots{list-style:none;display:flex;gap:5px;padding:0;margin:12px 0}
.tour-dots li{width:18px;height:4px;border-radius:2px;background:#ddd6ca}
.tour-dots li[data-active="true"]{background:var(--orange)}
.tour-actions{display:flex;align-items:center;gap:8px}
.tour-actions span{flex:1}
.tour-actions button{min-height:38px;border-radius:5px;padding:7px 13px;font-size:13px;font-weight:750;border:1px solid #bfc5c8;background:#fff;color:var(--ink)}
.tour-actions .tour-skip{border-color:transparent;color:var(--muted);padding-inline:4px}
.tour-actions .tour-next{background:var(--ink);border-color:var(--ink);color:#fff}
.tour-actions button[hidden]{display:none}
.tour-target{position:relative!important;z-index:61;background:var(--white);box-shadow:0 0 0 4px var(--white),0 0 0 7px var(--orange);border-radius:6px}
.tour-lift{z-index:61}
.model-note{border-top:1px solid #d7dfd8;padding-top:15px;font-size:13px;color:#4a5554;line-height:1.8}
.model-note strong{color:var(--ink)}
.sources{background:#e9e4d9;padding-block:95px}
.source-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}
.source-grid a{min-height:172px;padding:20px;background:rgba(255,253,249,.83);border-radius:7px;display:flex;flex-direction:column;border:1px solid transparent}
.source-grid a:hover{border-color:var(--orange);transform:translateY(-2px)}
.source-grid span{color:var(--orange);font-size:12px;font-weight:750;margin-bottom:12px}
.source-grid strong{font-size:17px;line-height:1.5}
.source-grid small{color:var(--muted);font-size:12px;line-height:1.6;margin-top:auto;padding-top:10px}
.figure-links{margin-top:28px;border-top:1px solid #cfc8bc;padding-top:23px}
.figure-links h3{font-size:18px;margin-bottom:2px}
.figure-links p{font-size:13px;color:var(--muted);margin-bottom:12px}
.figure-links ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px 20px}
.figure-links li{font-size:13px;line-height:1.7;display:flex;gap:10px;flex-wrap:wrap}
.figure-links a{font-weight:750;color:var(--blue)}
.figure-links a:hover{text-decoration:underline}
.figure-links span{color:#59636a}
.source-note{color:#566069;font-size:13px;line-height:1.8;margin:24px 0 0;max-width:800px}
.footer{display:flex;justify-content:space-between;align-items:center;gap:15px;min-height:90px;color:var(--muted);font-size:13px}
@media(max-width:900px){.hero{gap:5%;grid-template-columns:1fr .8fr}.hero-visual{height:390px}.orbit{transform:translate(-50%,-48%) scale(.83)}.research-grid{gap:5%}.cards,.source-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.lab-layout{grid-template-columns:1fr}}
@media(max-width:650px){.wrap{width:min(100% - 32px,1120px)}.topbar{min-height:66px;padding-inline:16px}.topbar nav{gap:12px;font-size:12px}.topbar nav a:first-child{display:none}.hero{display:block;min-height:0;padding-block:58px 66px}.hero h1{font-size:48px}.lead{font-size:17px}.hero-visual{height:340px;margin-top:45px;border-radius:140px 140px 8px 8px}.orbit{transform:translate(-50%,-47%) scale(.7)}.visual-bottom{gap:6px;left:12px;right:12px;font-size:10px}.research,.sources{padding-block:65px}.research-grid{display:block}.research-body>p{font-size:15px}.takeaway{grid-template-columns:1fr;gap:7px}.library{padding-block:70px}.library-heading{display:block}.section-note{margin-bottom:18px}.tools{display:block}.search-label{max-width:none}.filters{justify-content:flex-start;margin-top:17px}.cards,.source-grid,.figure-links ul{grid-template-columns:1fr}.lab-panel{padding:18px}.lab-top h3{font-size:24px}.lab-top{align-items:center}.result-value{font-size:29px}.footer{align-items:flex-start;flex-direction:column;justify-content:center}}
@media(max-width:650px){
  .lab-layout{display:flex;flex-direction:column;gap:0}
  .controls,.result-board{display:contents}
  .level-box{order:1}
  .result-label{order:2}.result-value{order:3;margin-bottom:8px}
  .scene{order:4}.scene-caption{order:5}
  .toggle-param,.param{order:6}
  .lab-actions{order:7;margin-top:6px}
  .hint-text,.feedback{order:8}
  .chart{order:9;margin-top:22px}.chart-caption{order:10}
  .toolbox{order:11}
  .scene text{font-size:17px}
  .chart text{font-size:17px}
  .lab-panel[data-flagship="true"] .scene{position:sticky;top:6px;z-index:4;box-shadow:0 6px 16px rgba(35,43,52,.14)}
  .level-steps{gap:5px;margin-bottom:14px}
  .level-steps button{flex-direction:column;align-items:flex-start;gap:4px;padding:7px 8px;min-height:64px}
  .step-title{white-space:normal;font-size:12px}
  .step-state{font-size:10px}
  .lab-top-actions{flex-direction:column}
  .tour-card{left:16px;right:16px;bottom:16px;width:auto}
  .formula-list div{grid-template-columns:1fr;gap:2px}
}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.lab-card,.source-grid a{transition:none}}