:root{--bg-color: #faf8ef;--grid-bg: #bbada0;--tile-bg: #eee4da;--text-color: #776e65;--button-bg: #8f7a66;--button-hover: #9f8a76;--button-active: #7f6a56;--button-text: #f9f6f2;--grid-size: 4;--gap-size: 7px;--total-gaps: 21px;--empty-cell-bg: rgba(238, 228, 218, .35);--tile-border-radius: 3px;--tile-2-bg: #eee4da;--tile-2-text: #776e65;--tile-4-bg: #ede0c8;--tile-4-text: #776e65;--tile-8-bg: #f2b179;--tile-8-text: #f9f6f2;--tile-16-bg: #f59563;--tile-16-text: #f9f6f2;--tile-32-bg: #f67c5f;--tile-32-text: #f9f6f2;--tile-64-bg: #f65e3b;--tile-64-text: #f9f6f2;--tile-128-bg: #edcf72;--tile-128-text: #f9f6f2;--tile-256-bg: #edcc61;--tile-256-text: #f9f6f2;--tile-512-bg: #edc850;--tile-512-text: #f9f6f2;--tile-1024-bg: #edc53f;--tile-1024-text: #f9f6f2;--tile-2048-bg: #edc22e;--tile-2048-text: #f9f6f2}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Inter,Clear Sans,Helvetica Neue,Arial,sans-serif;background-color:var(--bg-color);color:var(--text-color);line-height:1.6;min-height:100vh;display:flex;justify-content:center;align-items:center;padding:20px;transition:background-color .3s ease}#app{width:100%;max-width:600px}.game-container{background-color:var(--bg-color);border-radius:10px;padding:20px;box-shadow:0 4px 20px #0000001a}.header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:20px;flex-wrap:wrap;gap:20px;max-width:500px;margin-left:auto;margin-right:auto}#title{font-size:3.5rem;font-weight:700;color:#776e65;margin:0;line-height:1}.controls{display:flex;gap:10px;align-items:stretch;flex-wrap:wrap}.score-best-container{display:flex;flex-direction:row;gap:10px}.score-container{background-color:#bbada0;color:#fff;padding:5px 20px;text-align:center;min-width:90px}.score-label{font-size:.75rem;font-weight:700;text-transform:uppercase;letter-spacing:.5px}.score-value{font-weight:700}.new-game-btn{background-color:var(--button-bg);color:var(--button-text);border:none;padding:10px 24px;border-radius:3px;font-size:.9rem;font-weight:700;cursor:pointer;transition:all .2s ease;text-transform:uppercase;letter-spacing:.5px;white-space:nowrap;box-shadow:0 2px 4px #0000001a}.new-game-btn:hover{background-color:var(--button-hover);box-shadow:0 3px 6px #00000026;transform:translateY(-1px)}.new-game-btn:active{background-color:var(--button-active);box-shadow:0 1px 2px #0000001a;transform:translateY(1px)}.game-status-container{display:flex;justify-content:flex-end;align-items:center;margin-bottom:20px;gap:20px;flex-wrap:wrap;max-width:500px;margin-left:auto;margin-right:auto}.game-status{flex:1;text-align:left;font-size:1rem;color:var(--text-color);font-weight:500}.game-status strong{color:#8f7a66}.grid-container{background-color:var(--grid-bg);padding:15px;margin-bottom:20px;position:relative;width:100%;aspect-ratio:1;max-width:500px;margin-left:auto;margin-right:auto}.grid-background{position:absolute;inset:15px;display:grid;grid-template-columns:repeat(var(--grid-size),1fr);grid-template-rows:repeat(var(--grid-size),1fr);gap:var(--gap-size);z-index:0}.grid-cell{background-color:var(--empty-cell-bg);border-radius:var(--tile-border-radius)}.tile-container{position:absolute;inset:15px;z-index:10}.tile{position:absolute;width:calc((100% - var(--total-gaps)) / var(--grid-size));height:calc((100% - var(--total-gaps)) / var(--grid-size));background-color:var(--tile-bg);border-radius:var(--tile-border-radius);display:flex;justify-content:center;align-items:center;font-size:2.5rem;font-weight:700;color:var(--text-color);transition:transform .25s ease-out,opacity .25s ease-out;will-change:transform}.tile-new{animation:tileAppear .2s ease-out}.tile-merged{animation:tileMerge .3s ease-out}.tile-2{background-color:var(--tile-2-bg);color:var(--tile-2-text)}.tile-4{background-color:var(--tile-4-bg);color:var(--tile-4-text)}.tile-8{background-color:var(--tile-8-bg);color:var(--tile-8-text)}.tile-16{background-color:var(--tile-16-bg);color:var(--tile-16-text)}.tile-32{background-color:var(--tile-32-bg);color:var(--tile-32-text)}.tile-64{background-color:var(--tile-64-bg);color:var(--tile-64-text)}.tile-128{background-color:var(--tile-128-bg);color:var(--tile-128-text);font-size:1.8rem}.tile-256{background-color:var(--tile-256-bg);color:var(--tile-256-text);font-size:1.8rem}.tile-512{background-color:var(--tile-512-bg);color:var(--tile-512-text);font-size:1.8rem}.tile-1024{background-color:var(--tile-1024-bg);color:var(--tile-1024-text);font-size:1.6rem}.tile-2048{background-color:var(--tile-2048-bg);color:var(--tile-2048-text);font-size:1.6rem}.instructions{text-align:center;font-size:.85rem;line-height:1.6;color:#776e65;padding:12px 20px;background-color:#eee4da59;border-radius:6px;max-width:500px;margin:0 auto;font-weight:500}.instructions p{margin:0}.instructions strong{color:#776e65;font-weight:700}@keyframes tileAppear{0%{opacity:0;transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(0)}50%{transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(1.15)}to{opacity:1;transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(1)}}@keyframes tileMerge{0%{transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(1)}50%{transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(1.25)}70%{transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(1.1)}to{transform:translate(var(--tile-x, 0),var(--tile-y, 0)) scale(1)}}@media (max-width: 600px){body{padding:10px}.game-container{padding:15px}#title{font-size:2.5rem}.header{flex-direction:row;justify-content:space-between;align-items:flex-start;max-width:100%}.controls{justify-content:flex-end}.score-container{min-width:70px;padding:6px 15px}.score-label{font-size:.7rem}.score-value{font-size:1.1rem}.game-status-container{flex-direction:column;align-items:stretch;gap:15px;max-width:100%}.game-status{text-align:center;font-size:1rem}.new-game-btn{padding:10px 20px;font-size:.85rem;width:100%}.grid-container{max-width:100%}.instructions{font-size:.75rem;padding:10px;max-width:100%}.tile{font-size:1.8rem;width:calc((100% - var(--total-gaps)) / var(--grid-size));height:calc((100% - var(--total-gaps)) / var(--grid-size))}.tile-128,.tile-256,.tile-512{font-size:1.4rem}.tile-1024,.tile-2048{font-size:1.2rem}}@media (max-width: 400px){#title{font-size:2rem}.score-container{min-width:60px;padding:5px 12px}.score-label{font-size:.65rem}.score-value{font-size:1rem}.game-status{font-size:.9rem}.new-game-btn{padding:8px 16px;font-size:.75rem}.instructions{font-size:.7rem;padding:8px}.tile{font-size:1.4rem;width:calc((100% - var(--total-gaps)) / var(--grid-size));height:calc((100% - var(--total-gaps)) / var(--grid-size))}.tile-128,.tile-256,.tile-512{font-size:1.1rem}.tile-1024,.tile-2048{font-size:.95rem}}