:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --surface-light: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.4);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    max-width: 600px;
    width: 100%;
}

.game-header {
    text-align: center;
    margin-bottom: 40px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 10px;
}

.logo-icon {
    width: 48px;
    height: 48px;
    color: var(--primary-color);
}

h1 {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 16px;
    margin-top: 8px;
}

.game-container {
    background: var(--surface-color);
    border-radius: 24px;
    padding: 30px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.game-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--surface-light);
    border-radius: 16px;
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.2);
}

.stat-icon {
    width: 24px;
    height: 24px;
    color: var(--primary-color);
}

.stat-content {
    display: flex;
    flex-direction: column;
}

.stat-label {
    font-size: 12px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

.difficulty-selector {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
}

.difficulty-btn {
    flex: 1;
    padding: 12px 16px;
    background: var(--surface-light);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.difficulty-btn svg {
    width: 18px;
    height: 18px;
}

.difficulty-btn:hover {
    background: var(--primary-dark);
    border-color: var(--primary-color);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.difficulty-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

.puzzle-board {
    display: grid;
    gap: 8px;
    margin-bottom: 30px;
    aspect-ratio: 1;
    background: var(--bg-color);
    padding: 12px;
    border-radius: 16px;
    border: 2px solid var(--border-color);
}

.puzzle-tile {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: 800;
    color: white;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    user-select: none;
}

.puzzle-tile:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.puzzle-tile.empty {
    background: transparent;
    box-shadow: none;
    cursor: default;
}

.puzzle-tile.empty:hover {
    transform: none;
}

.puzzle-tile.moveable {
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    }
    50% {
        box-shadow: 0 4px 20px rgba(99, 102, 241, 0.6);
    }
}

.game-controls {
    display: flex;
    gap: 15px;
}

.control-btn {
    flex: 1;
    padding: 16px 24px;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.control-btn svg {
    width: 20px;
    height: 20px;
}

.control-btn.primary {
    background: var(--primary-color);
    color: white;
}

.control-btn.primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.4);
}

.control-btn.secondary {
    background: var(--surface-light);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.control-btn.secondary:hover {
    background: var(--warning-color);
    border-color: var(--warning-color);
    transform: translateY(-2px);
}

.win-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(10px);
}

.win-modal.show {
    display: flex;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.win-content {
    background: var(--surface-color);
    border-radius: 24px;
    padding: 50px;
    text-align: center;
    max-width: 400px;
    border: 2px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.4s ease;
}

@keyframes slideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.win-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, var(--success-color), #34d399);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: bounce 0.6s ease;
}

.win-icon svg {
    width: 48px;
    height: 48px;
    color: white;
}

@keyframes bounce {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.2);
    }
}

.win-content h2 {
    font-size: 36px;
    margin-bottom: 10px;
    background: linear-gradient(135deg, var(--success-color), #34d399);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.win-content p {
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-size: 18px;
}

.win-stats {
    display: flex;
    gap: 30px;
    justify-content: center;
    margin-bottom: 30px;
}

.win-stat {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 18px;
    font-weight: 600;
}

.win-stat svg {
    width: 20px;
    height: 20px;
    color: var(--primary-color);
}

.game-footer {
    text-align: center;
    margin-top: 30px;
    color: var(--text-secondary);
    font-size: 14px;
}

@media (max-width: 640px) {
    h1 {
        font-size: 36px;
    }

    .game-container {
        padding: 20px;
    }

    .game-stats {
        grid-template-columns: 1fr;
    }

    .difficulty-selector {
        flex-direction: column;
    }

    .puzzle-tile {
        font-size: 24px;
    }

    .win-content {
        padding: 30px;
        margin: 20px;
    }

    .win-stats {
        flex-direction: column;
        gap: 15px;
    }
}