#root{width:100%;min-height:100svh}:root{color:#24231f;font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;font-optical-sizing:auto;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light;--paper:#f6f5f0;--surface:#fbfaf7;--ink:#24231f;--muted:#77746c;--quiet:#a49f95;--line:#e7e4db;--accent:#cb6848;--accent-dark:#a94e35;--board:#e8e4db;--empty:#f3f0e9;background:#f6f5f0;font-family:Inter,Noto Sans SC,PingFang SC,Microsoft YaHei,-apple-system,BlinkMacSystemFont,Segoe UI,ui-sans-serif,sans-serif;font-weight:400}*{box-sizing:border-box}html{scroll-behavior:smooth;min-width:320px;min-height:100%}body{background:var(--paper);min-width:320px;min-height:100svh;margin:0}button,a{color:inherit;font:inherit}button{-webkit-tap-highlight-color:transparent}button:focus-visible,a:focus-visible,summary:focus-visible{outline-offset:3px;outline:3px solid #cb684866}::selection{color:var(--ink);background:#efc5b4}.app-shell{min-height:100svh;padding:max(22px, env(safe-area-inset-top)) max(18px, env(safe-area-inset-right)) max(22px, env(safe-area-inset-bottom)) max(18px, env(safe-area-inset-left));justify-content:center;display:flex}.game-wrap{width:min(100%,440px);margin:clamp(28px,8vh,70px) auto 0}.title-row{justify-content:space-between;align-items:flex-end;gap:12px;margin-bottom:18px;display:flex}h1{color:var(--ink);letter-spacing:-.075em;margin:0;font-family:Georgia,Times New Roman,serif;font-size:clamp(48px,14vw,66px);font-weight:500;line-height:.98}.title-period{color:var(--accent)}.mode-switch{border:1px solid var(--line);background:#fbfaf7b3;border-radius:9px;align-items:center;gap:2px;margin-bottom:3px;padding:3px;display:inline-flex}.mode-switch button{min-width:48px;min-height:36px;color:var(--muted);font:inherit;cursor:pointer;background:0 0;border:0;border-radius:6px;padding:0 11px;font-size:12px;transition:background .15s,color .15s}.mode-switch button.selected{background:var(--ink);color:#fffdf8}.score-row{align-items:center;gap:20px;min-height:44px;margin:0 0 12px;display:flex}.score-item{flex-direction:column;justify-content:center;gap:2px;min-width:48px;display:flex}.score-item span{color:var(--muted);font-size:10px}.score-item strong{color:var(--ink);font-variant-numeric:tabular-nums;font-size:18px;font-weight:600;line-height:1.1}.new-game,.skill-action,.skill-cancel{border:1px solid var(--line);background:var(--surface);min-height:38px;color:var(--ink);font:inherit;cursor:pointer;border-radius:8px;justify-content:center;align-items:center;padding:0 13px;font-size:12px;transition:border-color .15s,background .15s,transform .15s;display:inline-flex}.new-game{border-color:var(--accent);background:var(--accent);color:#fffaf6;margin-left:auto;font-weight:600}.new-game:hover{border-color:var(--accent-dark);background:var(--accent-dark)}.new-game:active,.skill-action:active,.skill-cancel:active{transform:translateY(1px)}.skill-strip{min-height:35px;margin:0 0 10px}.skill-actions{align-items:center;gap:8px;min-height:35px;display:flex}.skill-action{color:#8f4a34;background:#fbf2ec;border-color:#e2c5b8;min-height:32px;padding:0 10px}.skill-action:disabled{border-color:var(--line);color:#aaa59b;cursor:not-allowed;background:#f4f2ed}.skill-action b{margin-left:5px;font-size:10px;font-weight:600}.skill-cancel{min-height:31px;color:var(--muted);padding:0 10px}.skill-progress,.skill-prompt{color:var(--muted);font-size:10px;line-height:1.4}.skill-progress{white-space:nowrap}.skill-progress i{color:#c7bfb2;margin:0 4px;font-style:normal}.skill-prompt{color:var(--accent-dark)}.board{aspect-ratio:1;background:var(--board);touch-action:none;-webkit-user-select:none;user-select:none;border-radius:12px;grid-template-rows:repeat(4,minmax(0,1fr));grid-template-columns:repeat(4,minmax(0,1fr));gap:8px;width:100%;max-width:440px;padding:10px;display:grid;position:relative;overflow:hidden;box-shadow:0 2px 10px #342c230e}.board-cell{background:var(--empty);border-radius:8px;min-width:0;min-height:0}.tile{z-index:1;background:0 0;place-items:center;min-width:0;min-height:0;display:grid;position:relative}.tile-face{color:#514d44;font-variant-numeric:tabular-nums;letter-spacing:-.055em;transform-origin:50%;background:#f7f5ef;border-radius:8px;place-items:center;width:100%;height:100%;font-size:clamp(21px,7.2vw,34px);font-weight:600;display:grid}.tile--target{cursor:pointer}.tile--target .tile-face{box-shadow:inset 0 0 0 2px #cb684899}.tile--target:hover .tile-face{background:#f7e9df}.tile-face.tile-4{color:#4f4a41;background:#eee9dd}.tile-face.tile-8{color:#54392e;background:#e8b79f}.tile-face.tile-16{color:#fffaf5;background:#dc9677}.tile-face.tile-32{color:#fffaf5;background:#d47a59}.tile-face.tile-64{color:#fffaf5;background:#bd6042}.tile-face.tile-128,.tile-face.tile-256{color:#fffaf5;background:#55534d;font-size:clamp(19px,6vw,29px)}.tile-face.tile-512,.tile-face.tile-1024,.tile-face.tile-2048{color:#fffaf5;background:#282722;font-size:clamp(16px,5.4vw,25px)}.tile-face.tile-2048{background:var(--accent-dark)}.game-overlay{z-index:3;-webkit-backdrop-filter:blur(3px);backdrop-filter:blur(3px);background:#f6f5f0e0;flex-direction:column;justify-content:center;align-items:center;gap:12px;display:flex;position:absolute;inset:0}.game-overlay strong{font-family:Georgia,Times New Roman,serif;font-size:28px;font-weight:500}.board-hint{color:var(--muted);text-align:center;margin:12px 0 0;font-size:10px}.live-status{min-height:16px;color:var(--accent-dark);text-align:center;margin:6px 0 0;font-size:10px}button:focus-visible,.tile:focus-visible{outline-offset:3px;outline:3px solid #cb684873}@media (width>=700px){.board{border-radius:14px;gap:10px;padding:12px}.tile{border-radius:9px}}@media (width<=370px){.app-shell{padding-left:14px;padding-right:14px}.game-wrap{margin-top:24px}.title-row{margin-bottom:15px}.score-row{gap:14px}.skill-progress{font-size:9px}.board{gap:6px}}@media (prefers-reduced-motion:reduce){*,:before,:after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important;animation-iteration-count:1!important}}