: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,#f2f8f5);color:var(--ink);font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;min-height:100vh}body[data-theme=dark]{--card:#112036;--ink:#edf5ff;--muted:#aabbd0;--line:#29405c;background:#091321}.topbar{min-height:76px;padding:12px 20px;background:linear-gradient(135deg,#0b2948,var(--navy));color:#fff;display:flex;align-items:center;gap:14px}.back{color:#fff;text-decoration:none;border:1px solid rgba(255,255,255,.35);border-radius:12px;padding:9px 12px}.title{font-size:clamp(23px,3vw,36px);font-weight:850}.lesson{padding:7px 12px;border-radius:999px;background:var(--blue);font-weight:750}.top-actions{margin-left:auto;display:flex;gap:8px}button{font:inherit;min-height:44px;border:1px solid var(--line);border-radius:12px;padding:9px 12px;background:var(--card);color:var(--ink);font-weight:720;cursor:pointer}button:disabled{cursor:not-allowed;opacity:.45}.topbar button{background:rgba(255,255,255,.1);color:#fff;border-color:rgba(255,255,255,.3)}button:focus-visible,.switch:focus-visible,input:focus-visible{outline:3px solid rgba(35,100,170,.28);outline-offset:2px}.app{max-width:1580px;margin:auto;padding:16px}.layout{display:grid;grid-template-columns:285px minmax(560px,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}.head{padding:13px 15px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;align-items:center;gap:12px}.head h2{font-size:18px;margin:0}.body{padding:15px}.seg{display:grid;grid-template-columns:1fr 1fr;padding:4px;background:rgba(35,100,170,.08);border-radius:13px;margin-bottom:14px}.seg button{border:0;background:transparent}.seg .active{background:var(--blue);color:#fff}.count-control{padding:12px;border:1px solid var(--line);border-radius:14px;background:rgba(35,100,170,.045);margin-bottom:4px}.count-title{display:flex;align-items:center;justify-content:space-between;font-weight:750}.count-title output{min-width:66px;text-align:center;padding:4px 9px;border-radius:999px;background:var(--blue);color:#fff}.count-control input{width:100%;margin:12px 0 3px;accent-color:var(--blue);cursor:pointer}.range-ends{display:flex;justify-content:space-between;color:var(--muted);font-size:12px}.toggle{display:flex;justify-content:space-between;align-items:center;padding:11px 0;border-bottom:1px solid var(--line)}.switch{width:48px;height:27px;border-radius:999px;background:#cbd6e3;position:relative;cursor:pointer}.switch::after{content:"";position:absolute;width:21px;height:21px;border-radius:50%;background:#fff;left:3px;top:3px;transition:.18s}.switch.on{background:var(--teal)}.switch.on::after{left:24px}.actions{display:grid;grid-template-columns:1fr 1fr;gap:9px;margin-top:14px}.primary{background:var(--blue);color:#fff;border-color:var(--blue)}.hint{background:var(--orange);color:#fff;border-color:var(--orange)}.status{margin-top:14px;padding:13px;border-radius:14px;background:rgba(15,138,112,.08);line-height:1.55}.status strong{display:block;color:var(--teal);font-size:18px}.board-card .body{padding:10px}.board-tools{display:flex;align-items:center;gap:10px}.zoom-controls{display:flex;align-items:center;gap:5px}.zoom-controls button{min-width:36px;min-height:34px;padding:5px 9px;border-radius:9px}.zoom-controls .fit-view{font-size:13px}.zoom-level{min-width:48px;text-align:center;color:var(--muted);font-size:13px;font-variant-numeric:tabular-nums}.board-wrap{position:relative;min-height:660px;border:1px solid var(--line);border-radius:14px;overflow:hidden;background-color:#fbfdff}body[data-theme=dark] .board-wrap{background-color:#0d1b2e}canvas{width:100%;height:650px;display:block;touch-action:none;cursor:grab}canvas.is-dragging{cursor:grabbing}.board-note{position:absolute;left:14px;bottom:12px;max-width:calc(100% - 28px);padding:8px 11px;border-radius:10px;background:color-mix(in srgb,var(--card) 90%,transparent);border:1px solid var(--line);font-size:13px;color:var(--muted);pointer-events:none}.sequence{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}.sequence span{width:36px;height:36px;display:grid;place-items:center;border-radius:10px;color:#fff;font-weight:800}.task{padding:14px;border:1px solid #bfd1e8;border-radius:14px;background:rgba(35,100,170,.06);font-weight:750;line-height:1.55;margin-bottom:12px}.properties{display:grid;gap:9px}.prop{padding:11px 12px;border:1px solid var(--line);border-radius:12px;font-family:Georgia,"Times New Roman",serif;font-size:16px}.prop.locked{filter:blur(5px);user-select:none}.reveal{width:100%;margin-top:12px}.teacher{margin-top:14px;padding:13px;border:1px solid rgba(208,113,47,.35);border-radius:14px;background:rgba(208,113,47,.08);line-height:1.6}body.focus .sidebar,body.focus .evidence{display:none}body.focus .layout{grid-template-columns:1fr}
    @media(max-width:1120px){.layout{grid-template-columns:270px 1fr}.evidence{grid-column:1/-1}}@media(max-width:760px){.topbar{flex-wrap:wrap}.top-actions{margin-left:0}.layout{grid-template-columns:1fr}.evidence{grid-column:auto}.board-card .head{align-items:flex-start}.board-tools{align-items:flex-end;flex-direction:column;gap:5px}.board-wrap{min-height:520px}canvas{height:510px}.title{font-size:23px}.fit-view{display:none}}