:root{font-family:system-ui,Avenir,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;color-scheme:light dark;color:#ffffffde;background-color:#242424;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}a{font-weight:500;color:#646cff;text-decoration:inherit}a:hover{color:#535bf2}body{margin:0;display:flex;place-items:center;min-width:320px;min-height:100vh}h1{font-size:3.2em;line-height:1.1}button{border-radius:8px;border:1px solid transparent;padding:.6em 1.2em;font-size:1em;font-weight:500;font-family:inherit;background-color:#1a1a1a;cursor:pointer;transition:border-color .25s}button:hover{border-color:#646cff}button:focus,button:focus-visible{outline:4px auto -webkit-focus-ring-color}@media (prefers-color-scheme: light){:root{color:#213547;background-color:#fff}a:hover{color:#747bff}button{background-color:#f9f9f9}}body:before{content:"";position:fixed;top:0;left:0;width:100%;height:100%;background:radial-gradient(circle at 20% 80%,rgba(120,119,198,.3) 0%,transparent 50%),radial-gradient(circle at 80% 20%,rgba(255,119,198,.3) 0%,transparent 50%),radial-gradient(circle at 40% 40%,rgba(120,200,255,.3) 0%,transparent 50%);z-index:-1;animation:backgroundShift 20s infinite linear}@keyframes backgroundShift{0%,to{transform:translate(0) rotate(0)}33%{transform:translate(30px,-30px) rotate(120deg)}66%{transform:translate(-20px,20px) rotate(240deg)}}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Helvetica Neue,Segoe UI,Roboto,Arial,sans-serif;font-weight:400;background:linear-gradient(135deg,#667eea,#764ba2);color:#2c3e50;font-size:16px;line-height:1.65;min-height:100vh;overflow-x:hidden}.app{text-align:center;padding:20px;max-width:600px;margin:20px auto 0;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);background:#ffffff1a;border-radius:20px;box-shadow:0 20px 40px #0000001a;border:1px solid rgba(255,255,255,.2)}.game-container{position:relative;margin:0 auto}.game-header{margin-bottom:25px}.game-title{font-size:64px;font-weight:900;background:linear-gradient(45deg,#ff6b6b,#4ecdc4,#45b7d1,#96ceb4);background-size:300% 300%;background-clip:text;-webkit-background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:15px;text-shadow:0 4px 20px rgba(0,0,0,.1);animation:gradientShift 3s ease-in-out infinite}@keyframes gradientShift{0%,to{background-position:0% 50%}50%{background-position:100% 50%}}.game-intro{font-size:16px;line-height:24px;margin-bottom:30px;color:#ffffffe6;font-weight:500;text-shadow:0 2px 4px rgba(0,0,0,.2)}.game-controls{display:flex;justify-content:space-between;align-items:center;margin-bottom:25px;gap:20px}.score-container{display:flex;gap:15px}.score-box{background:linear-gradient(135deg,#fff3,#ffffff1a);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);padding:12px 20px;border-radius:15px;color:#fff;text-align:center;min-width:85px;border:1px solid rgba(255,255,255,.2);box-shadow:0 8px 16px #0000001a;transition:all .3s ease}.score-box:hover{transform:translateY(-2px);box-shadow:0 12px 24px #00000026}.score-label{font-size:12px;font-weight:700;text-transform:uppercase;margin-bottom:5px;letter-spacing:1px;opacity:.9}.score-value{font-size:20px;font-weight:900;text-shadow:0 2px 4px rgba(0,0,0,.2)}.score-animate{animation:scoreGlow .6s ease-out}@keyframes scoreGlow{0%{transform:scale(1);box-shadow:0 8px 16px #0000001a}50%{transform:scale(1.1);box-shadow:0 12px 24px #4ecdc466,0 0 20px #4ecdc44d}to{transform:scale(1);box-shadow:0 8px 16px #0000001a}}.new-game-button{background:linear-gradient(135deg,#ff6b6b,#ee5a52);color:#fff;border:none;border-radius:15px;padding:12px 25px;font-size:16px;font-weight:700;cursor:pointer;transition:all .3s ease;box-shadow:0 8px 16px #ff6b6b4d;text-transform:uppercase;letter-spacing:1px}.new-game-button:hover{transform:translateY(-3px) scale(1.05);box-shadow:0 12px 24px #ff6b6b66;background:linear-gradient(135deg,#ee5a52,#ff6b6b)}.new-game-button:active{transform:translateY(-1px) scale(1.02)}.game-board-container{position:relative;margin:0 auto;width:520px;height:520px;perspective:1000px}.game-board{position:relative;background:linear-gradient(135deg,#ffffff1a,#ffffff0d);-webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);border-radius:20px;width:520px;height:520px;padding:20px;display:grid;grid-template-columns:repeat(4,1fr);grid-template-rows:repeat(4,1fr);gap:20px;border:2px solid rgba(255,255,255,.2);box-shadow:0 20px 40px #00000026,inset 0 2px 4px #ffffff1a;transform-style:preserve-3d}.grid-cell{position:relative;background:#ffffff0d;border-radius:10px;border:1px solid rgba(255,255,255,.1);-webkit-backdrop-filter:blur(5px);backdrop-filter:blur(5px)}.tile{position:absolute;top:0;left:0;width:100%;height:100%;background:linear-gradient(135deg,#ff9a9e,#fecfef);border-radius:10px;display:flex;justify-content:center;align-items:center;font-size:48px;font-weight:900;color:#2c3e50;transition:all .3s cubic-bezier(.4,0,.2,1);box-shadow:0 8px 16px #0000001a,0 4px 8px #0000000d;border:1px solid rgba(255,255,255,.2);transform-style:preserve-3d}.tile:hover{transform:translateZ(10px) scale(1.02);box-shadow:0 12px 24px #00000026,0 6px 12px #0000001a}.tile-2{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff}.tile-4{background:linear-gradient(135deg,#f093fb,#f5576c);color:#fff}.tile-8{background:linear-gradient(135deg,#4facfe,#00f2fe);color:#fff}.tile-16{background:linear-gradient(135deg,#43e97b,#38f9d7);color:#fff}.tile-32{background:linear-gradient(135deg,#fa709a,#fee140);color:#fff}.tile-64{background:linear-gradient(135deg,#a8edea,#fed6e3);color:#2c3e50}.tile-128{background:linear-gradient(135deg,#ff9a9e,#fecfef);color:#fff;font-size:42px;box-shadow:0 12px 24px #ff9a9e66,0 6px 12px #0000001a;animation:pulse 2s infinite}.tile-256{background:linear-gradient(135deg,#a8e6cf,#dcedc8);color:#2c3e50;font-size:42px;box-shadow:0 12px 24px #a8e6cf66,0 6px 12px #0000001a;animation:pulse 2s infinite}.tile-512{background:linear-gradient(135deg,#ffd89b,#19547b);color:#fff;font-size:42px;box-shadow:0 12px 24px #ffd89b66,0 6px 12px #0000001a;animation:glow 2s infinite}.tile-1024{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;font-size:36px;box-shadow:0 16px 32px #667eea80,0 8px 16px #00000026;animation:glow 1.5s infinite}.tile-2048{background:linear-gradient(135deg,#f093fb,#f5576c,#4facfe);background-size:200% 200%;color:#fff;font-size:36px;box-shadow:0 20px 40px #f093fb99,0 10px 20px #0003;animation:rainbow 2s infinite,glow 1s infinite}.tile-4096,.tile-8192,.tile-16384{background:linear-gradient(135deg,#2c3e50,#34495e,#1e3c72);background-size:200% 200%;color:#ecf0f1;font-size:32px;box-shadow:0 24px 48px #2c3e5099,0 12px 24px #0000004d;animation:rainbow 3s infinite,superGlow 1.5s infinite}@keyframes pulse{0%,to{transform:scale(1)}50%{transform:scale(1.05)}}@keyframes glow{0%,to{box-shadow:0 16px 32px #667eea80,0 8px 16px #00000026}50%{box-shadow:0 20px 40px #667eeab3,0 10px 20px #0003}}@keyframes rainbow{0%{background-position:0% 50%}50%{background-position:100% 50%}to{background-position:0% 50%}}@keyframes superGlow{0%,to{box-shadow:0 24px 48px #2c3e5099,0 12px 24px #0000004d}50%{box-shadow:0 32px 64px #2c3e50cc,0 16px 32px #0006}}.game-over-overlay{position:absolute;top:0;left:0;width:100%;height:100%;background:#000000b3;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-radius:20px;display:flex;justify-content:center;align-items:center;z-index:100;animation:fadeIn .5s ease}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.game-over-content{text-align:center;background:#ffffff1a;padding:40px;border-radius:20px;border:1px solid rgba(255,255,255,.2);-webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);animation:slideUp .5s ease}@keyframes slideUp{0%{transform:translateY(50px);opacity:0}to{transform:translateY(0);opacity:1}}.game-over-title{font-size:48px;font-weight:900;color:#fff;margin-bottom:30px;text-shadow:0 4px 8px rgba(0,0,0,.3);background:linear-gradient(45deg,#ff6b6b,#4ecdc4);background-clip:text;-webkit-background-clip:text;-webkit-text-fill-color:transparent}.restart-button{background:linear-gradient(135deg,#4ecdc4,#44a08d);color:#fff;border:none;border-radius:15px;padding:15px 35px;font-size:18px;font-weight:700;cursor:pointer;transition:all .3s ease;box-shadow:0 8px 16px #4ecdc44d;text-transform:uppercase;letter-spacing:1px}.restart-button:hover{transform:translateY(-3px) scale(1.05);box-shadow:0 12px 24px #4ecdc466;background:linear-gradient(135deg,#44a08d,#4ecdc4)}.game-instructions{margin-top:30px;max-width:520px;margin-left:auto;margin-right:auto;text-align:center;line-height:1.8;background:#ffffff1a;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);padding:20px;border-radius:15px;border:1px solid rgba(255,255,255,.2);color:#ffffffe6}.game-instructions p{margin-bottom:10px;font-weight:500}.tile-new{animation:tileAppear .3s cubic-bezier(.68,-.55,.265,1.55)}@keyframes tileAppear{0%{transform:scale(0) rotate(180deg);opacity:0}50%{transform:scale(1.2) rotate(90deg);opacity:.8}to{transform:scale(1) rotate(0);opacity:1}}@media screen and (max-width: 600px){.app{padding:15px;margin-top:10px}.game-title{font-size:48px}.game-board-container{width:340px;height:340px}.game-board{width:340px;height:340px;padding:15px;gap:15px}.tile{font-size:32px}.tile-128,.tile-256,.tile-512{font-size:28px}.tile-1024,.tile-2048{font-size:24px}.tile-4096,.tile-8192,.tile-16384{font-size:20px}.game-over-title{font-size:36px}.game-controls{flex-direction:column;gap:15px}.score-container{justify-content:center}.game-instructions{font-size:14px;padding:15px}}