:root{--bg: #f6f4ef;--fg: #1f2328;--muted: #656d76;--card: #ffffff;--border: #ddd8cc;--accent: #2f6f4f;--accent-fg: #fff;--danger: #c0392b;--ok: #17703c;--warn: #8f5d12;--board-bg: #e0b86a;--board-line: #3a2a10;--board-coord: #5b4520;--mark-empty: #2a1d08;--label-empty: #1a1204;--ring-good: #1faa55;--ring-bad: #e0352b;--ring-info: #2f7be0;--radius: 10px;color-scheme:light dark}@media (prefers-color-scheme: dark){:root{--bg: #15171a;--fg: #e6e6e6;--muted: #9aa3ad;--card: #1f2328;--border: #343a41;--accent: #5cb88a;--accent-fg: #04100a;--danger: #ef6b5d;--ok: #46c27a;--warn: #e0a84a;--board-bg: #b48a45;--board-line: #2a1d08;--board-coord: #e8d6ae}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.6 system-ui,Noto Sans TC,PingFang TC,Microsoft JhengHei,sans-serif}a{color:var(--accent)}.app-nav{display:flex;align-items:center;gap:4px;padding:8px 12px;background:var(--card);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:5;overflow-x:auto}.app-nav a{padding:6px 12px;border-radius:8px;text-decoration:none;color:var(--fg);white-space:nowrap;line-height:1.4}.app-nav a.active{background:var(--accent);color:var(--accent-fg)}.app-nav .brand{display:inline-flex;align-items:center;gap:8px;font-weight:700;margin-right:8px;white-space:nowrap;flex-shrink:0}.app-nav .logo{position:relative;width:26px;height:20px;flex-shrink:0}.app-nav .logo i{position:absolute;top:2px;width:16px;height:16px;border-radius:50%}.app-nav .logo .s-b{left:0;background:radial-gradient(circle at 35% 35%,#555,#111 70%)}.app-nav .logo .s-w{left:10px;background:radial-gradient(circle at 35% 35%,#fff,#d4d4d4 75%);box-shadow:0 0 0 1px #00000059}main{max-width:1000px;margin:0 auto;padding:16px}h1{font-size:1.5rem;margin:0 0 12px}h2{font-size:1.15rem;margin:20px 0 8px}.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:14px 16px}.grid3{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}.card.link{text-decoration:none;color:inherit;display:block}.card.link:hover{border-color:var(--accent)}.card h3{margin:0 0 4px}.muted{color:var(--muted)}.row{display:flex;gap:8px;flex-wrap:wrap;align-items:center}button,.btn{font:inherit;padding:8px 16px;border-radius:8px;border:1px solid var(--border);background:var(--card);color:var(--fg);cursor:pointer;text-decoration:none;display:inline-block}button.primary,.btn.primary{background:var(--accent);color:var(--accent-fg);border-color:var(--accent)}button.danger{color:var(--danger);border-color:var(--danger)}button:disabled{opacity:.5;cursor:not-allowed}select,input{font:inherit;padding:6px 10px;border-radius:8px;border:1px solid var(--border);background:var(--card);color:var(--fg)}.err{color:var(--danger)}.ok{color:var(--ok)}.warn{color:var(--warn)}.two-col{display:grid;gap:16px;grid-template-columns:minmax(0,1fr)}@media (min-width: 820px){.two-col{grid-template-columns:minmax(0,560px) minmax(0,1fr);align-items:start}}.board-wrap{width:100%;max-width:640px;margin:0 auto}.banner{padding:10px 14px;border-radius:8px;margin:8px 0;border:1px solid var(--border);background:var(--card)}.banner.good{border-color:var(--ok)}.banner.bad{border-color:var(--danger)}.progress{height:6px;background:var(--border);border-radius:3px;overflow:hidden;margin-bottom:12px}.progress>div{height:100%;background:var(--accent)}.choice{display:block;width:100%;text-align:left;margin:6px 0}.choice.right{border-color:var(--ok)}.choice.wrong{border-color:var(--danger)}table.moves{border-collapse:collapse;width:100%;font-size:.92rem}table.moves th,table.moves td{padding:4px 8px;text-align:left;border-bottom:1px solid var(--border)}table.moves tr{cursor:pointer}table.moves tr.sel{background:color-mix(in srgb,var(--accent) 18%,transparent)}table.moves tr.mistake td{color:var(--danger);font-weight:700}.table-scroll{max-height:360px;overflow:auto;border:1px solid var(--border);border-radius:8px}.chart{width:100%;height:auto;background:var(--card);border:1px solid var(--border);border-radius:8px}.tag{font-size:.8rem;padding:1px 8px;border-radius:99px;border:1px solid var(--border)}.tag.done{color:var(--ok);border-color:var(--ok)}.app-nav .spacer{flex:1}.app-nav .who{padding:0 8px;white-space:nowrap;color:var(--muted);font-size:.9rem;max-width:8em;overflow:hidden;text-overflow:ellipsis}.app-nav .logout{white-space:nowrap;flex-shrink:0;padding:4px 10px;font-size:.9rem;line-height:1.4}@media (max-width: 600px){.app-nav{gap:2px;padding:6px 8px}.app-nav .brand{margin-right:4px}.app-nav .brand-text{display:none}.app-nav a{padding:6px 9px}}@media (max-width: 420px){.app-nav .who{display:none}}.login{max-width:420px;margin:40px auto;padding:0 16px}.login label{display:block;margin:12px 0}.login input{display:block;width:100%;box-sizing:border-box;margin-top:4px;font-size:18px;padding:8px;letter-spacing:1px}.login .big{display:block;width:100%;font-size:1.4rem;padding:18px;margin:16px 0}.login .big-hint{font-size:1.3rem;font-weight:700;margin:24px 0}.login .toast{padding:16px;border-radius:10px;background:var(--card);border:1px solid var(--border);text-align:center}a.link{text-decoration:none;color:inherit}main:has(.lesson-view){padding:6px 12px 8px}.lesson-view{--lv-gap: 6px;height:calc(100vh - var(--nav-h, 49px) - 14px);height:calc(100dvh - var(--nav-h, 49px) - 14px);display:flex;flex-direction:column;gap:var(--lv-gap);min-height:0}.lv-head{display:flex;align-items:baseline;gap:8px;flex:none;white-space:nowrap}.lv-head h1{font-size:1.05rem;margin:0;flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;line-height:1.4}.lesson-view .progress{margin:0;flex:none}.lv-step{flex:1 1 0;min-height:0;display:flex;flex-direction:column;gap:var(--lv-gap)}.lv-text{flex:0 1 auto;min-height:3em;overflow-y:auto;overscroll-behavior:contain;font-size:15px;line-height:1.5}.lv-text p,.lv-text h1{margin:0 0 4px}.lv-text h1{font-size:1.3rem}.lv-board{flex:0 100 auto;width:100%;max-width:640px;align-self:center;aspect-ratio:1;min-height:220px;container-type:size;display:flex;justify-content:center;align-items:flex-start}.lv-board-in{width:min(100cqw,100cqh)}.lv-spacer{flex:1 1 0;min-height:0}.lv-fb{flex:none;min-height:4.6em;font-size:14px;line-height:1.45;display:flex;align-items:center}.lv-fb>*{margin:0;width:100%;padding:6px 10px}.lv-fb .lv-turn{padding-left:2px}.lv-choices{flex:none;display:flex;flex-direction:column;gap:4px}.lv-choices .choice{margin:0;padding:7px 12px;font-size:15px;line-height:1.35}.lv-actions{flex:none;display:flex;gap:8px;align-items:center;flex-wrap:wrap;min-height:44px}.lv-actions button,.lv-actions .btn{min-height:44px;padding-top:6px;padding-bottom:6px;display:inline-flex;align-items:center}.lv-finish .lv-text{overflow:visible;font-size:16px;padding-top:12px}.lv-finish{flex:0 0 auto}.lv-finish .lv-spacer{display:none}@media (min-width: 820px) and (min-height: 480px){.lesson-view{--lv-gap: 8px}.lv-step{display:grid;grid-template-columns:minmax(280px,1fr) minmax(0,1.25fr);grid-template-rows:auto auto auto auto 1fr;column-gap:24px;row-gap:8px}.lv-text{grid-column:1;grid-row:1;font-size:16px;max-height:100%}.lv-choices{grid-column:1;grid-row:2}.lv-fb{grid-column:1;grid-row:3}.lv-actions{grid-column:1;grid-row:4;align-self:start}.lv-board{grid-column:2;grid-row:1 / 6;min-height:0;max-width:none;aspect-ratio:auto;width:auto;align-self:stretch}.lv-spacer{display:none}.lv-finish{display:flex}}