:root{--bg-color: #bbada0;--tile-bg: rgba(238, 228, 218, .35);--text-dark: #776e65;--text-light: #f9f6f2;--transition-speed: .1s}body{background-color:#faf8ef;color:var(--text-dark);font-family:Clear Sans,Helvetica Neue,Arial,sans-serif;display:flex;flex-direction:column;align-items:center;justify-content:center;height:100vh;margin:0;touch-action:none;overflow:hidden}.container{width:500px;max-width:95vw;display:flex;flex-direction:column;align-items:center;position:relative;user-select:none;-webkit-user-select:none}.modal{position:absolute;top:0;left:0;width:100%;height:100%;background:#eee4dae6;z-index:100;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;border-radius:6px;animation:fade-in .2s ease-in-out}.modal.hidden{display:none}.modal-content{background:#faf8ef;padding:30px;border-radius:8px;box-shadow:0 4px 15px #0003;max-width:90%;width:350px}.modal-content h2{font-size:40px;font-weight:700;color:#776e65;margin:0 0 20px}.modal-content p{font-size:18px;font-weight:700;color:#776e65;margin:10px 0}.modal-content input{background:#faf8ef;border:2px solid #bbada0;border-radius:3px;padding:10px 15px;font-size:18px;font-family:inherit;color:#776e65;width:80%;outline:none;margin-bottom:20px}.modal-content input:focus{border-color:#8f7a66}.modal-buttons{display:flex;justify-content:center;gap:10px;flex-wrap:wrap}#leaderboard-list{list-style:none;padding:0;margin:20px 0;max-height:300px;overflow-y:auto;text-align:left;width:100%}#leaderboard-list li{background:#eee4da;margin-bottom:8px;padding:10px;border-radius:4px;display:flex;justify-content:space-between;font-weight:700;color:#776e65}#leaderboard-list li span.rank{color:#8f7a66;margin-right:10px;width:20px;display:inline-block}.difficulty-tabs{display:flex;justify-content:center;margin-bottom:15px;gap:10px}.lb-tab{background:transparent;border:2px solid #8f7a66;color:#8f7a66;padding:5px 15px;font-size:14px;border-radius:15px;transition:all .2s}.lb-tab.active{background:#8f7a66;color:#fff}.header{display:flex;flex-direction:row;justify-content:space-between;align-items:center;width:100%;margin-bottom:20px}.header-top{display:flex;align-items:center;gap:15px}.header-buttons{display:flex;gap:8px}h1{font-size:60px;font-weight:700;margin:0;line-height:1;letter-spacing:-3px}.score-panel{display:flex;gap:5px;align-items:center}.score-container,.best-container{background:#bbada0;padding:8px 15px;border-radius:3px;color:#fff;text-align:center;min-width:50px}.score-label{text-transform:uppercase;font-size:10px;font-weight:700;display:block;color:#eee4da;margin-bottom:2px}.score-value{font-size:18px;font-weight:700}.difficulty-selector{display:flex;width:100%;background:#bbada0;border-radius:3px;padding:4px;margin:0 auto 20px}.diff-option{flex:1;background:transparent;border:none;padding:10px;color:#eee4da;font-size:16px;font-weight:700;cursor:pointer;border-radius:2px;transition:all .2s}.diff-option.active{background:#f9f6f2;color:#776e65}.icon-btn{background:#8f7a66;border:none;border-radius:3px;padding:8px;color:#fff;cursor:pointer;display:flex;align-items:center;justify-content:center;transition:background .2s}.icon-btn:hover{background:#7f6a56}.icon-btn svg{width:20px;height:20px;fill:currentColor}.grid-container{width:450px;height:450px;max-width:90vw;max-height:90vw;background:#bbada0;border-radius:6px;padding:12px;display:grid;grid-template-columns:repeat(4,1fr);grid-template-rows:repeat(4,1fr);gap:12px;position:relative;box-sizing:border-box;-webkit-user-select:none;user-select:none}.grid-cell{background:#eee4da59;border-radius:3px}.tile{position:absolute;transition:transform var(--transition-speed) ease-in-out;z-index:10}.tile-inner{width:100%;height:100%;border-radius:3px;display:flex;justify-content:center;align-items:center;font-size:50px;font-weight:700}.tile-2 .tile-inner{background:#eee4da;color:#776e65}.tile-4 .tile-inner{background:#ede0c8;color:#776e65}.tile-8 .tile-inner{background:#f2b179;color:#f9f6f2}.tile-16 .tile-inner{background:#f59563;color:#f9f6f2}.tile-32 .tile-inner{background:#f67c5f;color:#f9f6f2}.tile-64 .tile-inner{background:#f65e3b;color:#f9f6f2}.tile-128 .tile-inner{background:#edcf72;color:#f9f6f2;font-size:40px}.tile-256 .tile-inner{background:#edcc61;color:#f9f6f2;font-size:40px}.tile-512 .tile-inner{background:#edc850;color:#f9f6f2;font-size:40px}.tile-1024 .tile-inner{background:#edc53f;color:#f9f6f2;font-size:30px}.tile-2048 .tile-inner{background:#edc22e;color:#f9f6f2;font-size:30px}.tile-4096 .tile-inner{background:#3c3a32;color:#f9f6f2;font-size:30px}.tile-digits-3 .tile-inner{font-size:40px}.tile-digits-4 .tile-inner{font-size:30px}.tile-digits-5 .tile-inner{font-size:25px}@keyframes pop{0%{transform:scale(0);opacity:0}to{transform:scale(1);opacity:1}}@keyframes merge{0%{transform:scale(1)}50%{transform:scale(1.2)}to{transform:scale(1)}}.tile-new .tile-inner{animation:pop .2s ease-in-out}.tile-merged .tile-inner{animation:merge .2s ease-in-out;z-index:20}.controls{margin-top:20px;display:flex;justify-content:space-between;align-items:center;width:100%}.instructions{font-size:16px;line-height:1.5;color:#776e65}button{background:#8f7a66;border:none;border-radius:3px;padding:10px 20px;color:#f9f6f2;font-weight:700;cursor:pointer;font-size:16px}.footer{padding-top:20px;font-size:12px;color:#776e65;text-align:center}@media(max-width:520px){.container{width:100%;padding:0 10px;box-sizing:border-box}.header{margin-bottom:10px}h1{font-size:40px}.grid-container{width:90vw;height:90vw;padding:8px;gap:8px}.tile-inner{font-size:28px}.score-container,.best-container{padding:5px 10px}.score-value{font-size:16px}.modal-content{padding:20px;width:85%}.modal-content h2{font-size:30px}.controls{flex-direction:column-reverse;gap:15px;text-align:center}}@keyframes fade-in{0%{opacity:0}to{opacity:1}}