:root{--primary: #4fc3f7;--primary-light: #8bf6ff;--secondary: #4db6ac;--bg: #0a0a0a;--card-bg: rgba(30, 30, 30, .8);--text: #e0e0e0}*{box-sizing:border-box;margin:0;padding:0;font-family:Pretendard,-apple-system,BlinkMacSystemFont,system-ui,Roboto,sans-serif}body{background:var(--bg);color:var(--text);min-height:100vh;display:flex;justify-content:center;align-items:center;overflow-x:hidden}#root{width:100%;max-width:600px;padding:20px}.game-container{background:var(--card-bg);-webkit-backdrop-filter:blur(15px);backdrop-filter:blur(15px);border-radius:24px;padding:30px;box-shadow:0 20px 40px #00000080;text-align:center;border:1px solid rgba(255,255,255,.1)}h1{font-size:2rem;margin-bottom:20px;color:var(--primary);text-shadow:0 0 10px rgba(79,195,247,.3)}.difficulty-selector{display:flex;justify-content:center;gap:10px;margin-bottom:30px;flex-wrap:wrap}.btn{padding:10px 20px;border:none;border-radius:12px;background:#333;color:#fff;cursor:pointer;transition:all .3s cubic-bezier(.4,0,.2,1);box-shadow:0 4px 6px #0003;font-weight:600;text-transform:uppercase;letter-spacing:.5px}.btn:hover{background:#444;transform:translateY(-2px);box-shadow:0 8px 15px #0000004d}.btn.active{background:var(--primary);color:#fff;box-shadow:0 4px 12px #4fc3f766}.puzzle-board{display:grid;gap:4px;background:#1a1a1a;padding:8px;border-radius:16px;position:relative;aspect-ratio:1 / 1;margin:0 auto;max-width:450px;box-shadow:inset 0 0 20px #00000080}.tile{background-size:450px 450px;background-repeat:no-repeat;cursor:pointer;border-radius:8px;transition:all .2s ease;border:1px solid rgba(255,255,255,.05)}.tile:hover{filter:brightness(1.2);z-index:10;transform:scale(1.02)}.tile.empty{background:#121212;cursor:default;border:none}.stats{margin:20px 0;display:flex;justify-content:space-around;font-weight:700;font-size:1.1rem;color:var(--primary-light)}.controls{margin-top:20px;display:flex;gap:10px;justify-content:center}.success-overlay{position:fixed;top:0;left:0;width:100%;height:100%;background:#000000d9;display:flex;flex-direction:column;justify-content:center;align-items:center;z-index:100;color:#fff}.success-image{max-width:90%;max-height:70%;border-radius:20px;box-shadow:0 0 50px var(--primary);margin-bottom:20px}