:root{--navy:#16324f;--blue:#2364aa;--teal:#0f8a70;--orange:#d0712f;--rose:#c54b68;--bg:#f4f7fb;--card:#fff;--ink:#17243a;--muted:#637086;--line:#dbe5f1;--shadow:0 12px 30px rgba(22,50,79,.1)}
    *{box-sizing:border-box} body{margin:0;background:linear-gradient(135deg,#f8fbff,#f1f7f4);color:var(--ink);font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;min-height:100vh}
    body[data-theme="dark"]{--bg:#091321;--card:#112036;--ink:#edf5ff;--muted:#aabbd0;--line:#29405c;background:#091321}
    button,a{font:inherit}.topbar{min-height:76px;padding:12px 20px;background:linear-gradient(135deg,#0b2948,var(--navy));color:#fff;display:flex;align-items:center;gap:14px;box-shadow:0 8px 24px rgba(11,41,72,.18)}
    .back{color:#fff;text-decoration:none;border:1px solid rgba(255,255,255,.35);border-radius:12px;padding:9px 12px}.title{font-size:clamp(24px,3vw,38px);font-weight:850;letter-spacing:.02em}.lesson{padding:7px 12px;border-radius:999px;background:rgba(35,100,170,.9);font-weight:750}.top-actions{margin-left:auto;display:flex;gap:8px}
    button{border:1px solid var(--line);border-radius:12px;background:var(--card);color:var(--ink);padding:10px 13px;cursor:pointer;font-weight:720;min-height:44px}button:hover{filter:brightness(.97)}button:focus-visible,input:focus-visible{outline:3px solid rgba(35,100,170,.28);outline-offset:2px}.topbar button{background:rgba(255,255,255,.1);color:#fff;border-color:rgba(255,255,255,.28)}
    .app{max-width:1500px;margin:auto;padding:16px}.layout{display:grid;grid-template-columns:285px minmax(460px,1fr) 330px;gap:16px;align-items:start}.card{background:var(--card);border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);overflow:hidden}.card h2{font-size:18px;margin:0}.head{padding:14px 16px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;align-items:center}.body{padding:16px}
    .stage-number{font-size:56px;line-height:1;color:var(--blue);font-weight:850}.stage-label{font-size:17px;font-weight:750;margin-top:7px}.rule{margin:16px 0;padding:13px;border-radius:14px;background:rgba(35,100,170,.08);line-height:1.65}.rule b:nth-child(1){color:var(--blue)}.rule b:nth-child(2){color:var(--orange)}
    .range-row{margin:18px 0}.range-row label{display:flex;justify-content:space-between;font-size:14px;color:var(--muted);margin-bottom:8px}input[type=range]{width:100%;accent-color:var(--blue)}.controls{display:grid;grid-template-columns:1fr 1fr;gap:10px}.primary{background:var(--blue);border-color:var(--blue);color:#fff}.secondary{background:var(--teal);border-color:var(--teal);color:#fff}.zoom-actions{grid-column:1/-1;display:grid;grid-template-columns:minmax(0,1.65fr) minmax(82px,1fr);gap:10px}.zoom-actions button{min-height:58px;font-size:16px;padding:13px 8px}.zoom-control{border-color:var(--blue);background:rgba(35,100,170,.09);color:var(--blue);white-space:nowrap}.restore-control{border-color:var(--orange);background:rgba(208,113,47,.08);color:var(--orange)}.speed{display:flex;gap:8px;margin-top:12px}.speed button{flex:1}.speed button.active{background:var(--navy);color:#fff;border-color:var(--navy)}
    .canvas-card .body{padding:12px}.canvas-wrap{position:relative;min-height:610px;border-radius:14px;background:linear-gradient(180deg,rgba(35,100,170,.04),transparent),var(--card);display:flex;align-items:center;justify-content:center;overflow:hidden}canvas{width:100%;height:590px;display:block;cursor:grab;touch-action:none;user-select:none}canvas.dragging{cursor:grabbing}.caption{position:absolute;left:18px;right:18px;bottom:14px;display:flex;justify-content:space-between;gap:10px;align-items:center;padding:10px 13px;border:1px solid var(--line);border-radius:12px;background:color-mix(in srgb,var(--card) 90%,transparent);font-size:14px;pointer-events:none}.caption strong{color:var(--orange)}
    .formula{font-family:Georgia,"Times New Roman",serif;font-size:30px;text-align:center;padding:18px;border:1px solid #bfd1e8;border-radius:14px;background:rgba(35,100,170,.06);margin-bottom:12px}.metric{display:grid;grid-template-columns:1fr 1fr;gap:10px}.metric>div{padding:12px;border-radius:14px;background:rgba(15,138,112,.08);text-align:center}.metric small{display:block;color:var(--muted);margin-bottom:5px}.metric b{display:block;font-size:23px;color:var(--teal);font-family:Georgia,"Times New Roman",serif}.metric .decimal{display:block;margin-top:5px;color:var(--ink);font-size:17px;font-variant-numeric:tabular-nums}
    .bar{height:28px;border:1px solid var(--line);border-radius:999px;overflow:hidden;display:flex;margin:16px 0 8px;background:#fff}.sumbar{background:linear-gradient(90deg,var(--blue),var(--teal));transition:width .35s}.restbar{background:#fff;flex:1}.axis{display:flex;justify-content:space-between;color:var(--muted);font-size:12px}.takeaway{margin-top:16px;padding:14px;border:1px solid rgba(208,113,47,.35);border-radius:14px;background:rgba(208,113,47,.08);line-height:1.7}.takeaway strong{display:block;color:var(--orange);font-size:18px}.hidden-conclusion{filter:blur(7px);user-select:none}.reveal{width:100%;margin-top:12px}
    body.focus .sidebar,body.focus .evidence{display:none}body.focus .layout{grid-template-columns:1fr}.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
    @media(max-width:1050px){.layout{grid-template-columns:250px 1fr}.evidence{grid-column:1/-1}.canvas-wrap{min-height:520px}canvas{height:500px}}@media(max-width:760px){.topbar{align-items:flex-start;flex-wrap:wrap}.top-actions{margin-left:0}.layout{grid-template-columns:1fr}.evidence{grid-column:auto}.canvas-wrap{min-height:440px}canvas{height:420px}.caption{position:static;margin-top:8px}.title{font-size:24px}}
    @media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}