:root{--bg:#f7f6f2;--surface:#ffffff;--ink:#1d1d22;--muted:#5d5d68;--line:#dedcd4;--brand:#1f4e79;--brand-ink:#ffffff;--ok:#1e7a44;--bad:#b3261e;--warn:#9a6400;--soft:#eef2f7;--radius:10px;font-family:system-ui,-apple-system,Segoe UI,Roboto,Noto Sans,sans-serif;color-scheme:light}@media (prefers-color-scheme:dark){:root{--bg:#15161a;--surface:#1d1f24;--ink:#ecebe7;--muted:#a3a3ad;--line:#34363d;--brand:#7fb0e0;--brand-ink:#0d1520;--ok:#5fc18a;--bad:#f08a80;--warn:#e2b04a;--soft:#23272f;color-scheme:dark}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);line-height:1.5}a{color:var(--brand)}.wrap{max-width:980px;margin:0 auto;padding:0 16px}header.top{border-bottom:1px solid var(--line);background:var(--surface)}header.top .wrap{display:flex;align-items:center;gap:16px;height:56px}header.top .logo{font-weight:800;text-decoration:none;color:var(--ink);letter-spacing:.2px}header.top nav{margin-left:auto;display:flex;gap:14px;font-size:15px;flex-wrap:wrap}main{padding:24px 0 48px}footer.bottom{border-top:1px solid var(--line);padding:20px 0;color:var(--muted);font-size:14px}footer.bottom .wrap{display:flex;gap:14px;flex-wrap:wrap}h1{font-size:clamp(26px,4vw,36px);line-height:1.15;margin:8px 0 12px}h2{font-size:20px;margin:28px 0 10px}.muted{color:var(--muted)}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:16px}.grid{display:grid;grid-gap:12px;gap:12px;grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:42px;padding:0 18px;border-radius:8px;border:1px solid var(--brand);background:var(--brand);color:var(--brand-ink);font-weight:650;font-size:15px;cursor:pointer;text-decoration:none}.btn.ghost{background:transparent;color:var(--brand)}.btn:disabled{opacity:.55;cursor:not-allowed}.btn.danger{background:var(--bad);border-color:var(--bad);color:#fff}input,select,textarea{font:inherit;color:var(--ink);background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:9px 11px;min-height:42px;width:100%}label{display:block;font-weight:600;margin:12px 0 6px}.pill{display:inline-block;font-size:12px;font-weight:700;padding:2px 8px;border-radius:99px;background:var(--soft);color:var(--muted)}.pill.ok{color:var(--ok)}.err,.pill.bad{color:var(--bad)}.err{margin:10px 0}.note{background:var(--soft);border-radius:8px;padding:10px 12px;font-size:14px}table{width:100%;border-collapse:collapse}td,th{text-align:left;padding:8px;border-bottom:1px solid var(--line);font-size:14px}.player{display:grid;grid-template-columns:1fr 260px;grid-gap:16px;gap:16px;align-items:start}@media (max-width:760px){.player{grid-template-columns:1fr}}.bar{position:-webkit-sticky;position:sticky;top:0;z-index:5;background:var(--surface);border-bottom:1px solid var(--line);display:flex;align-items:center;gap:12px;padding:8px 0}.timer{font-feature-settings:"tnum";font-variant-numeric:tabular-nums;font-weight:800;font-size:20px}.timer.low{color:var(--bad)}.opt{display:flex;gap:10px;width:100%;text-align:left;padding:12px;margin:8px 0;border-radius:8px;border:1px solid var(--line);background:var(--surface);color:var(--ink);font:inherit;cursor:pointer}.opt[aria-pressed=true]{border-color:var(--brand);box-shadow:inset 0 0 0 1px var(--brand);background:var(--soft)}.opt.right{border-color:var(--ok);box-shadow:inset 0 0 0 1px var(--ok)}.opt.wrong{border-color:var(--bad);box-shadow:inset 0 0 0 1px var(--bad)}.opt b{min-width:22px}.palette{display:grid;grid-template-columns:repeat(auto-fill,minmax(38px,1fr));grid-gap:6px;gap:6px}.palette button{height:36px;border-radius:6px;border:1px solid var(--line);background:var(--surface);color:var(--ink);cursor:pointer;font:inherit;font-size:13px}.palette button.ans{background:var(--brand);color:var(--brand-ink);border-color:var(--brand)}.palette button.flag{outline:2px solid var(--warn);outline-offset:-2px}.palette button.cur{box-shadow:0 0 0 2px var(--ink)}.stem{font-size:17px;white-space:pre-wrap}.watermark{position:fixed;inset:0;pointer-events:none;z-index:50;opacity:.06;overflow:hidden;display:flex;flex-wrap:wrap;align-content:flex-start;gap:60px 80px;padding:40px;transform:rotate(-18deg) scale(1.3);font-size:14px;-webkit-user-select:none}.noselect,.watermark{-moz-user-select:none;user-select:none}.noselect{-webkit-user-select:none}dialog{border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);color:var(--ink);max-width:420px}dialog::-webkit-backdrop{background:rgb(0 0 0/.45)}dialog::backdrop{background:rgb(0 0 0/.45)}