/* 暖灰纸面配深色棋盘；不依赖字体、图片或任何外部 CDN。 */
:root{color-scheme:light;--paper:#ffffff;--ink:#26392f;--muted:#6b746a;--line:#d9ddd1;--green:#486951;--board:#182a26;--accent:#db774e}
*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:15px/1.65 system-ui,-apple-system,"Segoe UI","Microsoft YaHei",sans-serif}button{font:inherit;cursor:pointer;touch-action:manipulation}button:disabled{cursor:default;opacity:.45}button:focus-visible,summary:focus-visible{outline:3px solid var(--accent);outline-offset:4px}button:active:not(:disabled){transform:translateY(1px)}[hidden]{display:none!important}
.game-shell{max-width:640px;margin:auto;padding:28px 28px 20px}.game-header{display:flex;align-items:center;justify-content:space-between;gap:12px}.eyebrow{font-size:10px;letter-spacing:.2em;margin:0 0 8px;font-weight:650}.brand-mark{color:var(--accent);font-size:18px;vertical-align:middle;margin-right:5px}h1{font-family:Georgia,"Songti SC","SimSun",serif;font-size:32px;line-height:1.4;font-weight:500;margin:0}h1 span{display:block;font:11px/1.8 system-ui;letter-spacing:.18em;color:var(--muted);margin-top:2px}.status-pill{font-size:11px;border:1px solid #c6d1c1;background:#e9eee1;padding:5px 11px;border-radius:20px;white-space:nowrap}.status-pill::before{content:"";display:inline-block;width:5px;height:5px;background:var(--green);border-radius:50%;margin-right:6px}.intro{color:var(--muted);font-size:12px;margin:12px 0 22px}.scoreboard{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));padding:15px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);margin-bottom:22px}.scoreboard>div{padding:0 14px;border-left:1px solid var(--line)}.scoreboard>div:first-child{border:0;padding-left:0}.scoreboard span{display:block;font-size:10px;color:var(--muted)}.scoreboard strong{font-family:ui-monospace,Consolas,monospace;font-size:25px;font-weight:500;line-height:1.7;overflow-wrap:anywhere;font-variant-numeric:tabular-nums}
/* 棋盘始终保持 1:2 比例，右侧预览栏与其一起收缩。 */
.game-layout{display:grid;grid-template-columns:minmax(0,300px) 150px;justify-content:center;gap:22px;align-items:start}.board-wrap{position:relative;background:var(--board);padding:8px;border-radius:5px;box-shadow:0 5px 0 #ccd0c2,0 12px 28px #26392f0e;overflow:hidden}#board{display:block;width:100%;height:auto;aspect-ratio:1/2}.board-overlay{position:absolute;inset:8px;display:flex;align-items:center;justify-content:center;text-align:center;background:#182a26e8;color:#f4f2e8;padding:16px}.overlay-inner{width:100%}.overlay-kicker{color:#9cae98;font:9px/1.7 ui-monospace,monospace;letter-spacing:.16em;margin:0 0 18px}.board-overlay h2{font:500 29px/1.65 Georgia,"SimSun",serif;margin:0 0 14px}.board-overlay p:not(.overlay-kicker){font-size:11px;color:#b9c5b6;line-height:1.9;margin:0 0 25px}.primary{border:0;background:#dbe8c0;color:#213529;padding:12px 16px;border-radius:3px;min-height:44px;font-size:13px;min-width:130px}.primary span{margin-left:14px}
.sidebar{display:flex;flex-direction:column;gap:12px}.preview-card{border:1px solid var(--line);background:#eeeee4;border-radius:4px;padding:12px}.preview-card h2{margin:0 0 4px;font-size:11px;font-weight:500;display:flex;justify-content:space-between;align-items:center;gap:4px}.preview-card h2 span{font:9px ui-monospace,monospace;color:var(--muted);letter-spacing:.1em}#next,#hold{display:block;width:100%;height:auto}#hold-button{width:100%;padding:8px 0;border:0;border-top:1px solid var(--line);background:none;color:var(--ink);font-size:11px;min-height:40px}.secondary{border:1px solid var(--green);background:var(--green);color:#fff;padding:10px 5px;border-radius:3px;min-height:44px;font-size:12px}.quiet{border:1px solid var(--line);background:transparent;color:var(--muted);font-size:11px;min-height:42px}.side-note{font-size:10px;color:var(--muted);line-height:1.9;margin:2px 0}.sidebar kbd{border:0;background:none;font-size:10px;opacity:.65;margin-left:8px}
.touch-controls{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:8px;margin-top:24px}.touch-controls button{background:#e9eddf;border:1px solid #d2d9c8;border-bottom-width:3px;border-radius:4px;color:var(--ink);font-size:23px;line-height:1.2;min-height:60px;touch-action:none;user-select:none;-webkit-user-select:none}.touch-controls span{display:block;font-size:10px;margin-top:3px}.touch-controls .drop-button{background:#e7b58e;border-color:#d5a37b}.announcement{font-size:11px;color:var(--green);min-height:20px;margin:13px 0 18px}.instructions{border-top:1px solid var(--line);border-bottom:1px solid var(--line);font-size:11px}.instructions summary{cursor:pointer;list-style:none;padding:13px 0;display:flex;justify-content:space-between}.instructions summary::-webkit-details-marker{display:none}.instructions>div{padding-bottom:10px;color:var(--muted);line-height:2}.instructions p{margin:6px 0}kbd{font:10px ui-monospace,monospace;background:#e6e8de;border:1px solid #d0d6c8;border-radius:3px;padding:1px 4px}footer{display:flex;gap:12px;justify-content:space-between;color:var(--muted);font:9px/1.8 ui-monospace,monospace;letter-spacing:.04em;margin-top:18px;flex-wrap:wrap}
/* 手机缩小预览栏，保留五个足够大的触屏按钮，不禁用页面缩放。 */
@media(max-width:480px){.game-shell{padding:20px 14px 18px}h1{font-size:27px}.game-layout{grid-template-columns:minmax(0,1fr) 96px;gap:12px}.preview-card{padding:9px}.preview-card h2{font-size:10px}.preview-card h2 span{font-size:8px}.scoreboard>div{padding:0 8px}.scoreboard strong{font-size:22px}.board-overlay{padding:10px}.board-overlay h2{font-size:23px}.board-overlay p:not(.overlay-kicker){font-size:10px}.primary{min-width:0;width:100%;font-size:12px;padding:10px 8px}.overlay-kicker{font-size:8px}.side-note{font-size:9px}.touch-controls{gap:6px}.sidebar{gap:10px}.sidebar kbd{display:none}}
@media(prefers-reduced-motion:reduce){button:active:not(:disabled){transform:none}}