*{margin:0;padding:0;box-sizing:border-box}:root{--primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);--secondary-gradient: linear-gradient(145deg, #ffffff, #f0f0f0);--accent-color: #667eea;--text-primary: #4a5568;--text-secondary: #718096;--win-color: #38a169;--lose-color: #e53e3e;--border-radius: 15px;--box-shadow: 0 4px 15px rgba(0, 0, 0, .1);--transition: all .3s ease;--grid-bg: #bbada0;--cell-bg: rgba(238, 228, 218, .35);--text-dark: #776e65;--text-light: #f9f6f2;--tile-2: #eee4da;--tile-4: #ede0c8;--tile-8: #f2b179;--tile-16: #f59563;--tile-32: #f67c5f;--tile-64: #f65e3b;--tile-128: #edcf72;--tile-256: #edcc61;--tile-512: #edc850;--tile-1024: #edc53f;--tile-2048: #edc22e;--tile-super: #3c3a32}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;line-height:1.6;color:var(--text-primary);background:var(--primary-gradient);min-height:100vh;padding:1rem;display:flex;align-items:center;justify-content:center}.container{background:#fffffff2;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-radius:var(--border-radius);box-shadow:var(--box-shadow);padding:2rem;max-width:500px;width:100%;text-align:center}header h1{font-size:2.5rem;font-weight:700;color:var(--text-dark);margin-bottom:.5rem;text-shadow:1px 1px 2px rgba(0,0,0,.1)}header p{color:var(--text-secondary);font-size:1rem;margin-bottom:1.5rem}.game-controls{margin-bottom:1rem}.control-buttons{display:flex;gap:1rem;justify-content:center;flex-wrap:wrap}.control-btn{background:var(--accent-color);color:#fff;border:none;padding:.75rem 1.5rem;border-radius:var(--border-radius);font-size:.9rem;font-weight:600;cursor:pointer;transition:var(--transition);box-shadow:0 2px 8px #667eea4d}.control-btn:hover:not(:disabled){transform:translateY(-2px);box-shadow:0 4px 15px #667eea66}.control-btn:active{transform:translateY(0)}.control-btn:disabled{background:var(--text-secondary);cursor:not-allowed;box-shadow:none}.game-stats{margin-bottom:1.5rem}.stats-container{display:flex;justify-content:space-around;background:var(--secondary-gradient);padding:1rem;border-radius:var(--border-radius);box-shadow:inset 0 2px 4px #0000001a}.stat-item{text-align:center}.stat-label{display:block;font-size:.8rem;color:var(--text-secondary);font-weight:600;text-transform:uppercase;letter-spacing:.5px;margin-bottom:.25rem}.stat-value{display:block;font-size:1.2rem;font-weight:700;color:var(--text-dark)}.game-board-section{margin-bottom:1.5rem}.game-board{background:var(--grid-bg);border-radius:var(--border-radius);padding:.5rem;display:inline-block;box-shadow:var(--box-shadow);outline:none}.game-board:focus{box-shadow:0 0 0 3px #667eea4d,var(--box-shadow)}.grid-row{display:flex;margin-bottom:.5rem}.grid-row:last-child{margin-bottom:0}.grid-cell{width:80px;height:80px;background:var(--cell-bg);border-radius:8px;margin-right:.5rem;display:flex;align-items:center;justify-content:center;font-size:1.8rem;font-weight:700;transition:var(--transition);position:relative;overflow:hidden}.grid-cell:last-child{margin-right:0}.grid-cell.tile{color:var(--text-dark);transform:scale(1);animation:tileAppear .2s ease-out}.grid-cell.tile-2{background:var(--tile-2)}.grid-cell.tile-4{background:var(--tile-4)}.grid-cell.tile-8{background:var(--tile-8);color:var(--text-light)}.grid-cell.tile-16{background:var(--tile-16);color:var(--text-light)}.grid-cell.tile-32{background:var(--tile-32);color:var(--text-light)}.grid-cell.tile-64{background:var(--tile-64);color:var(--text-light)}.grid-cell.tile-128{background:var(--tile-128);color:var(--text-light);font-size:1.5rem;box-shadow:0 0 30px 10px #f3d7744d}.grid-cell.tile-256{background:var(--tile-256);color:var(--text-light);font-size:1.5rem;box-shadow:0 0 30px 10px #f3d77466}.grid-cell.tile-512{background:var(--tile-512);color:var(--text-light);font-size:1.5rem;box-shadow:0 0 30px 10px #f3d77480}.grid-cell.tile-1024{background:var(--tile-1024);color:var(--text-light);font-size:1.2rem;box-shadow:0 0 30px 10px #f3d77499}.grid-cell.tile-2048{background:var(--tile-2048);color:var(--text-light);font-size:1.2rem;box-shadow:0 0 30px 10px #f3d774cc;animation:tileWin .5s ease-out}.grid-cell.tile-super{background:var(--tile-super);color:var(--text-light);font-size:1rem}@keyframes tileAppear{0%{transform:scale(0);opacity:0}to{transform:scale(1);opacity:1}}@keyframes tileWin{0%,to{transform:scale(1)}50%{transform:scale(1.1)}}.grid-cell.merged{animation:tileMerge .3s ease-out}@keyframes tileMerge{0%{transform:scale(1)}50%{transform:scale(1.2)}to{transform:scale(1)}}.instructions{margin-bottom:1.5rem}.instructions h2{font-size:1.2rem;color:var(--text-dark);margin-bottom:.5rem}.instructions p{color:var(--text-secondary);font-size:.9rem;margin-bottom:.5rem}.instructions strong{color:var(--accent-color);font-weight:600}.game-status{margin-bottom:1rem}.status-message{background:var(--secondary-gradient);padding:1rem;border-radius:var(--border-radius);font-size:1.1rem;font-weight:600;box-shadow:var(--box-shadow);transition:var(--transition)}.status-message.hidden{display:none}.status-message.won{background:linear-gradient(145deg,#38a169,#2f855a);color:#fff;animation:statusPulse .5s ease-out}.status-message.lost{background:linear-gradient(145deg,#e53e3e,#c53030);color:#fff;animation:statusPulse .5s ease-out}@keyframes statusPulse{0%,to{transform:scale(1)}50%{transform:scale(1.05)}}footer{margin-top:1.5rem;padding-top:1rem;border-top:1px solid rgba(0,0,0,.1)}footer p{color:var(--text-secondary);font-size:.8rem}footer a{color:var(--accent-color);text-decoration:none;font-weight:600}footer a:hover{text-decoration:underline}@media (max-width: 600px){.container{padding:1.5rem;margin:.5rem}header h1{font-size:2rem}.grid-cell{width:65px;height:65px;font-size:1.5rem}.grid-cell.tile-128,.grid-cell.tile-256,.grid-cell.tile-512{font-size:1.2rem}.grid-cell.tile-1024,.grid-cell.tile-2048{font-size:1rem}.stats-container{flex-direction:column;gap:.5rem}.stat-item{display:flex;justify-content:space-between;align-items:center}.stat-label{margin-bottom:0}}@media (max-width: 400px){.grid-cell{width:55px;height:55px;font-size:1.3rem}.grid-cell.tile-128,.grid-cell.tile-256,.grid-cell.tile-512,.grid-cell.tile-1024,.grid-cell.tile-2048{font-size:.9rem}}