@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@300;400;500&display=swap');
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'JetBrains Mono', monospace;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            overflow: hidden;
            transition: all 0.5s ease;
        }
        
        /* Lofi Pink Theme (Default) */
        .theme-lofi {
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
            color: #e94560;
        }
        
        /* Black & White Theme */
        .theme-bw {
            background: linear-gradient(135deg, #0a0a0a 0%, #1a1a1a 50%, #2a2a2a 100%);
            color: #ffffff;
        }
        
        /* Cyberpunk Theme */
        .theme-cyber {
            background: linear-gradient(135deg, #0d1117 0%, #161b22 50%, #21262d 100%);
            color: #00d9ff;
        }
        
        .container {
            text-align: center;
            padding: 20px;
            backdrop-filter: blur(10px);
            border-radius: 20px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
            transition: all 0.5s ease;
        }
        
        .theme-lofi .container {
            border: 1px solid rgba(233, 69, 96, 0.2);
            background: rgba(26, 26, 46, 0.3);
        }
        
        .theme-bw .container {
            border: 1px solid rgba(255, 255, 255, 0.2);
            background: rgba(40, 40, 40, 0.3);
        }
        
        .theme-cyber .container {
            border: 1px solid rgba(0, 217, 255, 0.2);
            background: rgba(13, 17, 23, 0.3);
        }
        
        h1 {
            font-size: 2.5rem;
            margin-bottom: 10px;
            font-weight: 300;
            letter-spacing: 2px;
            animation: glow 2s ease-in-out infinite alternate;
            transition: all 0.5s ease;
        }
        
        .theme-lofi h1 {
            text-shadow: 0 0 20px rgba(233, 69, 96, 0.5);
        }
        
        .theme-bw h1 {
            text-shadow: 0 0 20px rgba(255, 255, 255, 0.5);
        }
        
        .theme-cyber h1 {
            text-shadow: 0 0 20px rgba(0, 217, 255, 0.5);
        }
        
        @keyframes glow {
            from { filter: brightness(1); }
            to { filter: brightness(1.2); }
        }
        
        .subtitle {
            font-size: 0.9rem;
            color: #5a5a7a;
            margin-bottom: 30px;
            font-weight: 300;
        }
        
        .puzzle-board {
            display: grid;
            gap: 8px;
            width: 320px;
            height: 320px;
            margin: 0 auto 30px;
            padding: 20px;
            border-radius: 15px;
            box-shadow: inset 0 4px 12px rgba(0, 0, 0, 0.3);
            transition: all 0.3s ease;
        }
        
        .theme-lofi .puzzle-board {
            background: rgba(15, 52, 96, 0.4);
            border: 2px solid rgba(233, 69, 96, 0.3);
        }
        
        .theme-bw .puzzle-board {
            background: rgba(20, 20, 20, 0.4);
            border: 2px solid rgba(255, 255, 255, 0.3);
        }
        
        .theme-cyber .puzzle-board {
            background: rgba(13, 17, 23, 0.4);
            border: 2px solid rgba(0, 217, 255, 0.3);
        }
        
        .size-3 {
            grid-template-columns: repeat(3, 1fr);
            width: 280px;
            height: 280px;
        }
        
        .size-4 {
            grid-template-columns: repeat(4, 1fr);
            width: 320px;
            height: 320px;
        }
        
        .size-5 {
            grid-template-columns: repeat(5, 1fr);
            width: 360px;
            height: 360px;
        }
        
        .tile {
            border: none;
            border-radius: 10px;
            color: white;
            font-family: 'JetBrains Mono', monospace;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            position: relative;
            overflow: hidden;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .theme-lofi .tile {
            background: linear-gradient(135deg, #e94560 0%, #c73650 100%);
            box-shadow: 0 4px 12px rgba(233, 69, 96, 0.3);
        }
        
        .theme-bw .tile {
            background: linear-gradient(135deg, #ffffff 0%, #e0e0e0 100%);
            color: #000000;
            box-shadow: 0 4px 12px rgba(255, 255, 255, 0.3);
        }
        
        .theme-cyber .tile {
            background: linear-gradient(135deg, #00d9ff 0%, #0099cc 100%);
            color: #000000;
            box-shadow: 0 4px 12px rgba(0, 217, 255, 0.3);
        }
        
        .size-3 .tile {
            font-size: 1.8rem;
        }
        
        .size-4 .tile {
            font-size: 1.5rem;
        }
        
        .size-5 .tile {
            font-size: 1.2rem;
        }
        
        .tile::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
            transition: left 0.5s;
        }
        
        .tile:hover {
            transform: translateY(-2px) scale(1.05);
        }
        
        .theme-lofi .tile:hover {
            box-shadow: 0 8px 25px rgba(233, 69, 96, 0.5);
            background: linear-gradient(135deg, #ff4d6d 0%, #d63447 100%);
        }
        
        .theme-bw .tile:hover {
            box-shadow: 0 8px 25px rgba(255, 255, 255, 0.5);
            background: linear-gradient(135deg, #f5f5f5 0%, #d5d5d5 100%);
        }
        
        .theme-cyber .tile:hover {
            box-shadow: 0 8px 25px rgba(0, 217, 255, 0.5);
            background: linear-gradient(135deg, #33e0ff 0%, #00b3dd 100%);
        }
        
        .tile:hover::before {
            left: 100%;
        }
        
        .tile:active {
            transform: translateY(0) scale(0.98);
        }
        
        .empty-tile {
            background: transparent !important;
            box-shadow: none !important;
        }
        
        .theme-lofi .empty-tile {
            border: 2px dashed rgba(233, 69, 96, 0.3);
            box-shadow: inset 0 0 10px rgba(233, 69, 96, 0.2) !important;
        }
        
        .theme-bw .empty-tile {
            border: 2px dashed rgba(255, 255, 255, 0.3);
            box-shadow: inset 0 0 10px rgba(255, 255, 255, 0.2) !important;
        }
        
        .theme-cyber .empty-tile {
            border: 2px dashed rgba(0, 217, 255, 0.3);
            box-shadow: inset 0 0 10px rgba(0, 217, 255, 0.2) !important;
        }
        
        .empty-tile:hover {
            transform: none !important;
            background: transparent !important;
        }
        
        .theme-lofi .empty-tile:hover {
            box-shadow: inset 0 0 15px rgba(233, 69, 96, 0.3) !important;
        }
        
        .theme-bw .empty-tile:hover {
            box-shadow: inset 0 0 15px rgba(255, 255, 255, 0.3) !important;
        }
        
        .theme-cyber .empty-tile:hover {
            box-shadow: inset 0 0 15px rgba(0, 217, 255, 0.3) !important;
        }
        
        .controls {
            display: flex;
            gap: 15px;
            justify-content: center;
            margin-bottom: 20px;
        }
        
        .btn {
            padding: 12px 24px;
            border: 2px solid;
            border-radius: 25px;
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.9rem;
            cursor: pointer;
            transition: all 0.3s ease;
            text-transform: uppercase;
            letter-spacing: 1px;
            font-weight: 400;
        }
        
        .theme-lofi .btn {
            background: linear-gradient(135deg, #16213e 0%, #0f3460 100%);
            border-color: rgba(233, 69, 96, 0.5);
            color: #e94560;
        }
        
        .theme-bw .btn {
            background: linear-gradient(135deg, #2a2a2a 0%, #1a1a1a 100%);
            border-color: rgba(255, 255, 255, 0.5);
            color: #ffffff;
        }
        
        .theme-cyber .btn {
            background: linear-gradient(135deg, #161b22 0%, #0d1117 100%);
            border-color: rgba(0, 217, 255, 0.5);
            color: #00d9ff;
        }
        
        .btn:hover {
            transform: translateY(-2px);
        }
        
        .theme-lofi .btn:hover {
            background: linear-gradient(135deg, #e94560 0%, #c73650 100%);
            color: white;
            box-shadow: 0 8px 20px rgba(233, 69, 96, 0.4);
        }
        
        .theme-bw .btn:hover {
            background: linear-gradient(135deg, #ffffff 0%, #e0e0e0 100%);
            color: #000000;
            box-shadow: 0 8px 20px rgba(255, 255, 255, 0.4);
        }
        
        .theme-cyber .btn:hover {
            background: linear-gradient(135deg, #00d9ff 0%, #0099cc 100%);
            color: #000000;
            box-shadow: 0 8px 20px rgba(0, 217, 255, 0.4);
        }
        
        .status {
            font-size: 1rem;
            color: #5a5a7a;
            margin-top: 20px;
            font-weight: 300;
        }
        
        .moves {
            font-weight: 500;
            transition: color 0.5s ease;
        }
        
        .theme-lofi .moves {
            color: #e94560;
        }
        
        .theme-bw .moves {
            color: #ffffff;
        }
        
        .theme-cyber .moves {
            color: #00d9ff;
        }
        
        .win-message {
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            padding: 40px;
            border-radius: 20px;
            border: 2px solid;
            font-size: 1.5rem;
            text-align: center;
            display: none;
            z-index: 1000;
            backdrop-filter: blur(20px);
            animation: fadeIn 0.5s ease-out;
            transition: all 0.5s ease;
        }
        
        .theme-lofi .win-message {
            background: rgba(26, 26, 46, 0.95);
            border-color: #e94560;
            color: #e94560;
            box-shadow: 0 0 50px rgba(233, 69, 96, 0.5);
        }
        
        .theme-bw .win-message {
            background: rgba(20, 20, 20, 0.95);
            border-color: #ffffff;
            color: #ffffff;
            box-shadow: 0 0 50px rgba(255, 255, 255, 0.5);
        }
        
        .theme-cyber .win-message {
            background: rgba(13, 17, 23, 0.95);
            border-color: #00d9ff;
            color: #00d9ff;
            box-shadow: 0 0 50px rgba(0, 217, 255, 0.5);
        }
        
        @keyframes fadeIn {
            from { opacity: 0; transform: translate(-50%, -50%) scale(0.8); }
            to { opacity: 1; transform: translate(-50%, -50%) scale(1); }
        }
        
        .particles {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            z-index: -1;
        }
        
        .particle {
            position: absolute;
            width: 2px;
            height: 2px;
            animation: float 6s infinite ease-in-out;
        }
        
        .theme-lofi .particle {
            background: rgba(233, 69, 96, 0.3);
        }
        
        .theme-bw .particle {
            background: rgba(255, 255, 255, 0.3);
        }
        
        .theme-cyber .particle {
            background: rgba(0, 217, 255, 0.3);
        }
        
        @keyframes float {
            0%, 100% { transform: translateY(100vh) rotate(0deg); opacity: 0; }
            10% { opacity: 1; }
            90% { opacity: 1; }
            100% { transform: translateY(-10px) rotate(360deg); opacity: 0; }
        }