:root{
  --ink:#1d1d1f;--ink2:#6e6e73;--line:rgba(0,0,0,.08);--accent:#0071e3;--accent2:#2d7cff;--ok:#34c759;--warn:#ff9f0a;
  --glass:rgba(255,255,255,.66);--glass-strong:rgba(255,255,255,.72);--rim:rgba(255,255,255,.75);
  --shadow:0 10px 40px rgba(18,38,63,.12),0 1px 2px rgba(18,38,63,.06);--r:18px;
  --ease:cubic-bezier(.2,.8,.2,1);--font:-apple-system,BlinkMacSystemFont,"SF Pro Text","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Segoe UI",system-ui,sans-serif;
}
*{box-sizing:border-box}
html,body{margin:0;min-height:100%}
body{font:15px/1.5 var(--font);color:var(--ink);background:radial-gradient(1200px 700px at 10% -10%,#dbe9f8 0,transparent 60%),radial-gradient(900px 600px at 110% 10%,#f6eadf 0,transparent 55%),#eef2f6;overflow-x:clip;-webkit-font-smoothing:antialiased}
a{color:var(--accent);text-decoration:none}
button,.btn{font:inherit;color:inherit;border:0;cursor:pointer;background:rgba(255,255,255,.7);border-radius:12px;padding:8px 14px;transition:background .2s var(--ease),transform .15s var(--ease),box-shadow .2s var(--ease),color .2s;display:inline-flex;align-items:center;gap:6px;justify-content:center;text-decoration:none;box-shadow:0 1px 2px rgba(0,0,0,.06)}
button:hover,.btn:hover{background:#fff}
button:active,.btn:active{transform:scale(.96)}
button:focus-visible,[role=slider]:focus-visible,a:focus-visible{outline:3px solid rgba(0,113,227,.45);outline-offset:2px}
.primary,.btn.primary{background:var(--accent);color:#fff;box-shadow:0 6px 18px rgba(0,113,227,.35)}
.primary:hover,.btn.primary:hover{background:#0077ed}
.muted{color:var(--ink2)} .small{font-size:12.5px}
.eyebrow{font-size:12px;letter-spacing:.06em;text-transform:uppercase;color:var(--ink2);font-weight:600}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.glass{background:var(--glass);-webkit-backdrop-filter:blur(24px) saturate(180%);backdrop-filter:blur(28px) saturate(160%);border:1px solid var(--rim);border-radius:var(--r);box-shadow:var(--shadow)}
.boot{position:fixed;inset:0;display:grid;place-items:center}
.spinner{width:28px;height:28px;border-radius:50%;border:3px solid rgba(0,0,0,.1);border-top-color:var(--accent);animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.enter{animation:enter .45s var(--ease) both}
@keyframes enter{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}

/* 顶栏 */
.topbar{position:fixed;z-index:30;top:10px;left:10px;right:10px;height:52px;display:flex;align-items:center;gap:18px;padding:0 10px 0 14px;border-radius:16px}
.brand{display:flex;align-items:center;gap:8px;font-weight:700;color:var(--ink);letter-spacing:-.01em}
.topbar nav{display:flex;gap:4px;flex:1;min-width:0}
.topbar nav a{color:var(--ink);padding:6px 12px;border-radius:10px;font-size:14px;transition:background .2s}
.topbar nav a:hover{background:rgba(255,255,255,.6)}
.topbar nav a.on{background:rgba(0,0,0,.06);font-weight:600}
.lang{padding:6px 12px;font-size:13px;font-weight:600}

/* 3D 舞台 */
.stage{position:absolute;inset:0;overflow:hidden}
.stage canvas{display:block;width:100%;height:100%;touch-action:none}

/* 设计器 */
.design,.learn{position:fixed;inset:0}
.dock{position:absolute;z-index:10;left:12px;top:50%;transform:translateY(-50%);width:78px;padding:8px;display:flex;flex-direction:column;gap:10px}
.dock .grp{display:flex;flex-direction:column;gap:6px}
.ib{flex-direction:column;gap:2px;padding:8px 4px;font-size:11px;background:transparent;box-shadow:none}
.ib[aria-pressed=true]{background:var(--accent);color:#fff;box-shadow:0 6px 16px rgba(0,113,227,.35)}
.seg{display:flex;background:rgba(0,0,0,.06);border-radius:11px;padding:3px;gap:2px}
.seg button{flex:1;background:transparent;box-shadow:none;padding:6px 6px;font-size:12.5px;border-radius:9px;flex-direction:column;gap:1px}
.seg button[aria-pressed=true]{background:#fff;box-shadow:0 2px 8px rgba(0,0,0,.1);font-weight:600}
.dock .seg{flex-direction:column}
.dock .seg button span{font-size:11px}
.seg.full{flex-direction:row}.seg.full button{flex-direction:row}
.insp{position:absolute;z-index:10;right:12px;top:74px;bottom:12px;width:308px;padding:16px;overflow:auto;scrollbar-width:thin}
.insp h4{margin:16px 0 8px;font-size:13px;color:var(--ink2);font-weight:600;display:flex;justify-content:space-between}
.cost{display:flex;flex-direction:column;gap:2px;padding:12px 14px;border-radius:14px;background:linear-gradient(135deg,rgba(0,113,227,.12),rgba(52,199,89,.10))}
.cost span{font-size:12px;color:var(--ink2)} .cost b{font-size:26px;letter-spacing:-.02em;font-variant-numeric:tabular-nums} .cost a{font-size:13px}
.card{margin-top:12px;padding:12px;border-radius:14px;background:rgba(255,255,255,.6)}
.card .row{justify-content:space-between}
.link{background:none;box-shadow:none;padding:2px 4px;color:var(--accent);font-size:13px}.link.danger{color:#ff3b30}
.mats{display:grid;grid-template-columns:1fr;gap:6px;margin-top:8px}
.mat{justify-content:flex-start;text-align:left;padding:6px;gap:10px;background:rgba(255,255,255,.55)}
.mat img{width:40px;height:40px;border-radius:9px;object-fit:cover;flex:none;box-shadow:inset 0 0 0 1px rgba(0,0,0,.06)}
.mat span{display:flex;flex-direction:column;line-height:1.25;min-width:0}.mat b{font-weight:600;font-size:13px}.mat i{font-style:normal;font-size:12px;color:var(--ink2)}
.mat[aria-pressed=true]{box-shadow:0 0 0 2px var(--accent);background:#fff}
.mats.compact{grid-template-columns:1fr 1fr}
.range{position:relative;padding:10px 4px;cursor:pointer}
.range.off{opacity:.4;pointer-events:none}
.track{position:relative;height:6px;border-radius:3px;background:rgba(0,0,0,.1)}
.fill{position:absolute;left:0;top:0;bottom:0;border-radius:3px;background:var(--accent)}
.knob{position:absolute;top:50%;width:22px;height:22px;margin:-11px 0 0 -11px;border-radius:50%;background:#fff;box-shadow:0 2px 8px rgba(0,0,0,.25);transition:left .25s var(--ease)}
.files{display:grid;grid-template-columns:1fr 1fr;gap:6px;margin-top:18px}
.tldock{position:absolute;z-index:10;left:102px;right:332px;bottom:12px;padding:10px 16px;display:flex;align-items:center;gap:14px}
.learn .tldock{left:12px;right:404px}
.play{width:40px;height:40px;border-radius:50%;padding:0;flex:none}
.tlwrap{flex:1;min-width:0;display:flex;flex-direction:column;gap:6px}
.timeline{cursor:pointer;padding:6px 0 0}
.timeline .track i{position:absolute;top:50%;width:6px;height:6px;margin:-3px 0 0 -3px;border-radius:50%;background:rgba(255,255,255,.9)}
.ticks{display:flex;justify-content:space-between;margin-top:8px;font-size:11px;color:var(--ink2)}
.ticks span{flex:1;text-align:center;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;transition:color .2s}
.ticks span:first-child{text-align:left}.ticks span:last-child{text-align:right}
.ticks span.on{color:var(--ink);font-weight:600}
.stage-cap{font-size:12.5px;color:var(--ink2);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.stage-cap b{color:var(--ink);margin-right:6px}
.hint{position:absolute;z-index:9;top:76px;left:50%;transform:translateX(-50%);padding:7px 14px;border-radius:99px;background:rgba(29,29,31,.72);color:#fff;font-size:13px;pointer-events:none;white-space:nowrap;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}
.hint.pop{animation:enter .35s var(--ease)}
.measure{position:fixed;z-index:40;left:0;top:0;pointer-events:none;padding:4px 10px;border-radius:99px;background:var(--accent);color:#fff;font-size:12.5px;font-weight:600;opacity:0;transition:opacity .15s}
.toast{position:fixed;z-index:50;left:50%;bottom:110px;transform:translate(-50%,20px);padding:10px 18px;border-radius:99px;background:rgba(29,29,31,.85);color:#fff;font-size:14px;opacity:0;pointer-events:none;transition:all .3s var(--ease)}
.toast.show{opacity:1;transform:translate(-50%,0)}
.modal{position:fixed;inset:0;z-index:60;display:grid;place-items:center;background:rgba(0,0,0,0);transition:background .25s}
.modal.in{background:rgba(0,0,0,.18)}
.modal .box{padding:22px;max-width:360px;margin:16px;transform:scale(.94);opacity:0;transition:all .25s var(--ease)}
.modal.in .box{transform:none;opacity:1}
.modal .row{justify-content:flex-end;margin-top:14px}

/* 章节 */
.lessonpane{position:absolute;z-index:10;right:12px;top:74px;bottom:12px;width:380px;padding:20px;overflow:auto;scrollbar-width:thin}
.lessonpane h2{margin:4px 0 6px;font-size:22px;letter-spacing:-.02em}
.steps{list-style:none;padding:0;margin:16px 0 0;display:flex;flex-direction:column;gap:8px}
.step{display:flex;gap:12px;padding:12px;border-radius:14px;background:rgba(255,255,255,.45);transition:background .3s,opacity .3s,box-shadow .3s}
.step .n{flex:none;width:26px;height:26px;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:700;background:rgba(0,0,0,.07)}
.step p{margin:2px 0}
.step[data-state=active]{background:#fff;box-shadow:0 6px 24px rgba(0,0,0,.08)}
.step[data-state=active] .n{background:var(--accent);color:#fff}
.step[data-state=done]{opacity:.72}.step[data-state=done] .n{background:var(--ok);color:#fff}
.step[data-state=todo]{opacity:.55}
.choices{display:flex;flex-direction:column;gap:6px;margin-top:8px}
.choices button{justify-content:flex-start;text-align:left;background:rgba(0,0,0,.04);box-shadow:none}
.choices button:hover{background:rgba(0,113,227,.1)}
.hintbox{margin-top:8px;padding:8px 10px;border-radius:10px;background:rgba(255,159,10,.14);font-size:13.5px}
.explain{font-size:13px;color:var(--ink2)}
.partinfo{margin-top:12px;padding:10px 12px;border-radius:12px;background:rgba(0,113,227,.1);font-size:14px}
.complete{margin-top:12px;padding:14px;border-radius:14px;background:rgba(52,199,89,.14)}
.complete .row{margin-top:10px}
.srcs{margin-top:16px;font-size:13px}.srcs a{display:block;margin:4px 0}

/* 首页 */
.hero{position:relative;height:100vh;min-height:560px}
.hero .stage{border-radius:0}
.herocard{position:absolute;z-index:5;left:max(24px,4vw);top:50%;transform:translateY(-44%);width:min(460px,calc(100% - 48px));padding:30px}
.herocard h1{font-size:clamp(30px,4vw,46px);line-height:1.08;letter-spacing:-.035em;margin:10px 0 12px}
.herocard p{color:#3a3a3c;margin:0 0 20px}
.course{max-width:1120px;margin:0 auto;padding:40px 16px 80px}
.course .head{display:flex;justify-content:space-between;align-items:flex-end;gap:16px;flex-wrap:wrap;margin-bottom:18px}
.course h2{font-size:30px;letter-spacing:-.03em;margin:0}
.prog{min-width:200px}.prog .bar{height:6px;border-radius:3px;background:rgba(0,0,0,.08);overflow:hidden;margin-bottom:6px}.prog .bar i{display:block;height:100%;background:var(--ok);transition:width .6s var(--ease)}.prog span{font-size:13px;color:var(--ink2)}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px}
.lcard{display:flex;flex-direction:column;gap:6px;padding:18px;color:var(--ink);transition:transform .25s var(--ease),box-shadow .25s var(--ease)}
.lcard:hover{transform:translateY(-3px);box-shadow:0 18px 50px rgba(18,38,63,.16)}
.lcard b{font-size:17px;letter-spacing:-.01em}.lcard p{margin:0;font-size:13.5px;color:var(--ink2)}
.lcard em{font-style:normal;color:var(--ok)}
.lcard[data-done=true]{background:rgba(236,251,240,.7)}
.house{display:flex;flex-direction:column;margin-top:18px;padding:18px 20px;color:var(--ink)}
.house b{font-size:28px;letter-spacing:-.02em}

/* 文档页 */
.doc{padding:84px 12px 60px}
.sheet{max-width:1040px;margin:0 auto;padding:28px}
.sheet h1{font-size:30px;letter-spacing:-.03em;margin:0 0 4px}
.sheet h3{margin:28px 0 10px}
.tablewrap{overflow-x:auto;margin-top:16px}
table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums}
th,td{padding:10px 10px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
th{font-size:12px;color:var(--ink2);font-weight:600}
td.r,th.r{text-align:right;white-space:nowrap}
tfoot td{border:0;font-size:17px;padding-top:14px}
.tag{font-size:11.5px;padding:2px 8px;border-radius:99px;background:rgba(0,0,0,.06);white-space:nowrap}.tag.warn{background:rgba(255,159,10,.18)}
.disclaimer{margin-top:18px;padding:12px 14px;border-radius:12px;background:rgba(255,159,10,.12);font-size:13.5px}
.method{padding-left:18px;font-size:14px}.method li{margin:4px 0}
.src{padding:12px 0;border-bottom:1px solid var(--line);font-size:14px;overflow-wrap:anywhere}
.src q{display:block;margin:4px 0;color:#3a3a3c;font-style:italic}
.texlist{list-style:none;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:8px}
.texlist li{display:flex;align-items:center;gap:8px}.texlist img{width:36px;height:36px;border-radius:8px}

/* 第一人称参观 */
.walk{position:fixed;inset:0}
.walk .stage canvas{cursor:crosshair}
.crosshair{position:absolute;z-index:5;left:50%;top:50%;width:18px;height:18px;margin:-9px 0 0 -9px;pointer-events:none}
.crosshair::before,.crosshair::after{content:"";position:absolute;background:rgba(255,255,255,.95);box-shadow:0 0 2px rgba(0,0,0,.6)}
.crosshair::before{left:8px;top:0;width:2px;height:18px}.crosshair::after{top:8px;left:0;height:2px;width:18px}
.aimtip{position:absolute;z-index:6;left:50%;top:calc(50% + 26px);transform:translate(-50%,6px);padding:6px 14px;border-radius:99px;background:rgba(29,29,31,.78);color:#fff;font-size:14px;font-weight:600;opacity:0;transition:all .2s var(--ease);pointer-events:none}
.aimtip.on{opacity:1;transform:translate(-50%,0)}
.whud{position:absolute;z-index:10;left:12px;bottom:12px;width:min(360px,calc(100% - 24px));padding:14px 16px;display:flex;flex-direction:column;gap:10px}
.row.between{justify-content:space-between}
.where{font-size:12.5px;font-weight:600;padding:3px 10px;border-radius:99px;background:rgba(0,113,227,.12);color:var(--accent)}
.keys{display:flex;flex-wrap:wrap;gap:6px 12px;font-size:12.5px;color:var(--ink2)}
kbd{display:inline-block;min-width:20px;padding:1px 6px;margin-right:2px;border-radius:6px;background:#fff;border:1px solid rgba(0,0,0,.12);box-shadow:0 1px 0 rgba(0,0,0,.12);font:600 11.5px/1.5 var(--font);color:var(--ink);text-align:center}
.wstart{position:absolute;z-index:20;inset:0;display:grid;place-items:center;background:rgba(10,20,30,.18);transition:opacity .3s var(--ease)}
.wstart.hide{opacity:0;pointer-events:none}
.wstart .card{max-width:420px;margin:16px;padding:26px;text-align:center}.wstart .card b{font-size:22px}.wstart .card p{color:#3a3a3c}
.joy{position:absolute;z-index:12;left:24px;bottom:150px;width:120px;height:120px;border-radius:50%;background:rgba(255,255,255,.28);border:1px solid rgba(255,255,255,.6);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);touch-action:none}
.joy i{position:absolute;left:50%;top:50%;width:52px;height:52px;margin:-26px 0 0 -26px;border-radius:50%;background:rgba(255,255,255,.9);box-shadow:0 4px 12px rgba(0,0,0,.2)}
.tbtns{position:absolute;z-index:12;right:18px;bottom:160px;display:flex;flex-direction:column;gap:12px}
.tbtns button{width:76px;height:76px;border-radius:50%;font-weight:700;background:rgba(255,255,255,.75);touch-action:none}
.walkbtn{color:var(--accent)}

/* 手机 */
@media (max-width:759px){
  .topbar{gap:8px;padding:0 6px 0 10px}.brand span{display:none}.topbar nav a{padding:6px 8px;font-size:13.5px}
  .design,.learn{position:static;padding:70px 8px 16px;display:flex;flex-direction:column;gap:8px}
  .design .stage,.learn .stage{position:relative;inset:auto;height:52vh;border-radius:16px;flex:none}
  .learn .stage{height:46vh}
  .dock,.insp,.tldock,.lessonpane{position:static;transform:none;width:auto;inset:auto}
  .dock{flex-direction:column;gap:6px;padding:6px}
  .dock .grp{flex-direction:row;flex-wrap:wrap;gap:4px}
  .dock .grp:first-child{justify-content:space-between}
  .dock .seg{flex-direction:row}
  .ib{flex:1;min-width:0}
  .dock .grp:last-child .seg{flex:1}
  .insp{max-height:none}
  .tldock{order:2}.dock{order:1}.insp{order:3}
  .ticks span{display:none}.ticks span.on{display:block;text-align:center}
  .hint{display:none}
  .walk .whud{bottom:auto;top:70px}
  .hero{height:78vh;min-height:520px}
  .herocard{top:auto;bottom:16px;transform:none;left:12px;width:calc(100% - 24px);padding:22px}
  .sheet{padding:18px}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}