:root {
    --bg-primary: #0f0f1a;
    --bg-secondary: #1a1b2e;
    --bg-card: rgba(26, 27, 46, 0.7);
    --bg-card-hover: rgba(35, 37, 62, 0.8);
    --border-subtle: rgba(255, 255, 255, 0.06);
    --border-accent: rgba(99, 102, 241, 0.3);
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #6366f1;
    --accent-light: #818cf8;
    --accent-glow: rgba(99, 102, 241, 0.4);
    --success: #22c55e;
    --success-bg: rgba(34, 197, 94, 0.12);
    --warning: #f59e0b;
    --warning-bg: rgba(245, 158, 11, 0.12);
    --danger: #ef4444;
    --danger-bg: rgba(239, 68, 68, 0.12);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 20px;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 20px var(--accent-glow);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    --cell-border: rgba(255, 255, 255, 0.02);
    --cell-inner: rgba(255, 255, 255, 0.12);
    --cell-shadow: rgba(0, 0, 0, 0.4);
    --overlay-bg: rgba(15, 15, 26, 0.92);
    --next-piece-bg: rgba(15, 15, 26, 0.5);
    --kbd-bg: rgba(255, 255, 255, 0.06);
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --bg-card: rgba(255, 255, 255, 0.8);
    --bg-card-hover: rgba(255, 255, 255, 0.95);
    --border-subtle: rgba(0, 0, 0, 0.08);
    --border-accent: rgba(99, 102, 241, 0.35);
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --accent: #6366f1;
    --accent-light: #818cf8;
    --accent-glow: rgba(99, 102, 241, 0.2);
    --success: #16a34a;
    --success-bg: rgba(34, 197, 94, 0.1);
    --warning: #d97706;
    --warning-bg: rgba(245, 158, 11, 0.1);
    --danger: #dc2626;
    --danger-bg: rgba(239, 68, 68, 0.08);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.15);
    --cell-border: rgba(0, 0, 0, 0.06);
    --cell-inner: rgba(255, 255, 255, 0.3);
    --cell-shadow: rgba(0, 0, 0, 0.15);
    --overlay-bg: rgba(248, 250, 252, 0.92);
    --next-piece-bg: rgba(241, 245, 249, 0.8);
    --kbd-bg: rgba(0, 0, 0, 0.06);
}

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

body {
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
    background-image:
        radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(139, 92, 246, 0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(59, 130, 246, 0.05) 0%, transparent 50%);
}

/* Header */
.game-header {
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Theme Toggle */
.theme-toggle {
    margin-left: auto;
    width: 38px;
    height: 38px;
    border-radius: 50%;
    border: 1px solid var(--border-subtle);
    background: var(--bg-card);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    transition: all 0.3s;
    backdrop-filter: blur(8px);
}

.theme-toggle:hover {
    border-color: var(--border-accent);
    box-shadow: var(--shadow-glow);
    transform: rotate(15deg);
}

.theme-icon-dark,
.theme-icon-light {
    position: absolute;
    font-size: 20px;
    transition: opacity 0.3s, transform 0.3s;
}

.theme-icon-light {
    opacity: 0;
    transform: scale(0.5) rotate(-30deg);
}

.theme-icon-dark {
    opacity: 1;
    transform: scale(1);
}

[data-theme="light"] .theme-icon-dark {
    opacity: 0;
    transform: scale(0.5) rotate(30deg);
}

[data-theme="light"] .theme-icon-light {
    opacity: 1;
    transform: scale(1);
}
.game-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.logo {
    font-family: var(--font-mono);
    font-size: 32px;
    font-weight: 800;
    letter-spacing: 8px;
    background: linear-gradient(135deg, var(--accent-light), #a78bfa, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-sub {
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    letter-spacing: 4px;
    padding: 3px 8px;
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
}

/* Layout */
.game-container {
    display: flex;
    gap: 24px;
}

.game-area {
    position: relative;
}

/* Board */
.board {
    display: grid;
    grid-template-columns: repeat(10, 30px);
    grid-template-rows: repeat(20, 30px);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    border: 1px solid var(--border-accent);
    box-shadow: var(--shadow-lg), inset 0 0 40px rgba(0, 0, 0, 0.5), var(--shadow-glow);
    overflow: hidden;
}

.cell {
    width: 30px;
    height: 30px;
    border: 1px solid var(--cell-border);
}

.cell[style*="background-color"] {
    border-radius: 3px;
    border: 1px solid var(--border-subtle);
    box-shadow:
        inset 0 -3px 6px var(--cell-shadow),
        inset 0 3px 6px var(--cell-inner),
        0 0 4px var(--accent-glow);
}

@keyframes lineClear {
    0% { transform: scaleY(1); opacity: 1; filter: brightness(2); }
    50% { transform: scaleY(1.05); opacity: 0.7; filter: brightness(3); }
    100% { transform: scaleY(0); opacity: 0; }
}

.line-clearing .cell {
    animation: lineClear 0.3s ease-out forwards;
}

/* Side Panel */
.side-panel {
    display: flex;
    flex-direction: column;
    gap: 12px;
    width: 200px;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
}

.stat-card {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    backdrop-filter: blur(12px);
    transition: all 0.2s;
}

.stat-card:hover {
    border-color: var(--border-accent);
    background: var(--bg-card-hover);
}

.stat-icon {
    font-size: 18px;
    opacity: 0.6;
    width: 24px;
    text-align: center;
    flex-shrink: 0;
}

.stat-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.stat-label {
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--text-muted);
}

.stat-value {
    font-family: var(--font-mono);
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

/* Cards */
.next-piece-card,
.controls-card,
.shortcuts-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 14px;
    backdrop-filter: blur(12px);
}

.card-header {
    margin-bottom: 10px;
}

.card-title {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--text-muted);
}

/* Next Piece */
.next-piece-display {
    display: grid;
    grid-template-columns: repeat(4, 24px);
    grid-template-rows: repeat(4, 24px);
    justify-content: center;
    min-height: 96px;
    background: var(--next-piece-bg);
    border-radius: var(--radius-md);
    padding: 8px;
    border: 1px solid var(--border-subtle);
}

.next-cell {
    width: 24px;
    height: 24px;
    border-radius: 3px;
}

.next-cell[style*="background-color"] {
    border-radius: 4px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow:
        inset 0 -2px 4px rgba(0, 0, 0, 0.3),
        inset 0 2px 4px rgba(255, 255, 255, 0.1);
}

/* Buttons */
.controls {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.3px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    outline: none;
    position: relative;
    overflow: hidden;
}

.btn-icon {
    font-size: 14px;
}

.btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

.btn-success {
    background: var(--success-bg);
    border-color: rgba(34, 197, 94, 0.25);
    color: var(--success);
}

.btn-success:hover:not(:disabled) {
    background: rgba(34, 197, 94, 0.2);
    border-color: rgba(34, 197, 94, 0.5);
    box-shadow: 0 0 16px rgba(34, 197, 94, 0.15);
    transform: translateY(-1px);
}

.btn-success:active:not(:disabled) {
    transform: translateY(0);
}

.btn-warning {
    background: var(--warning-bg);
    border-color: rgba(245, 158, 11, 0.25);
    color: var(--warning);
}

.btn-warning:hover:not(:disabled) {
    background: rgba(245, 158, 11, 0.2);
    border-color: rgba(245, 158, 11, 0.5);
    box-shadow: 0 0 16px rgba(245, 158, 11, 0.15);
    transform: translateY(-1px);
}

.btn-warning:active:not(:disabled) {
    transform: translateY(0);
}

.btn-danger {
    background: var(--danger-bg);
    border-color: rgba(239, 68, 68, 0.25);
    color: var(--danger);
}

.btn-danger:hover:not(:disabled) {
    background: rgba(239, 68, 68, 0.2);
    border-color: rgba(239, 68, 68, 0.5);
    box-shadow: 0 0 16px rgba(239, 68, 68, 0.15);
    transform: translateY(-1px);
}

.btn-danger:active:not(:disabled) {
    transform: translateY(0);
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent), #7c3aed);
    border: none;
    color: #fff;
    padding: 14px 32px;
    font-size: 15px;
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--accent-light), #8b5cf6);
    box-shadow: 0 4px 20px var(--accent-glow);
    transform: translateY(-2px);
}

.btn-lg {
    border-radius: var(--radius-lg);
}

/* Shortcuts */
.shortcuts-card {
    padding: 12px 14px;
}

.shortcut-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.shortcut-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--text-secondary);
}

kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 28px;
    padding: 2px 6px;
    font-family: var(--font-mono);
    font-size: 11px;
    background: var(--kbd-bg);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
}

/* Game Over Overlay */
.game-over-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--overlay-bg);
    backdrop-filter: blur(8px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10;
    border-radius: var(--radius-md);
    animation: overlayIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes overlayIn {
    from { opacity: 0; backdrop-filter: blur(0); }
    to { opacity: 1; backdrop-filter: blur(8px); }
}

.game-over-overlay.hidden {
    display: none;
}

.game-over-content {
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.game-over-icon {
    font-size: 48px;
    opacity: 0.8;
    animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.6; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.1); }
}

.game-over-content h2 {
    font-family: var(--font-mono);
    font-size: 28px;
    font-weight: 800;
    letter-spacing: 4px;
    color: var(--danger);
}

.final-score {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    margin: 4px 0 12px;
}

.final-score-label {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--text-muted);
}

.final-score-value {
    font-family: var(--font-mono);
    font-size: 40px;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

/* Responsive */
@media (max-width: 640px) {
    .game-wrapper { gap: 12px; }

    .game-container {
        flex-direction: column;
        align-items: center;
        gap: 16px;
    }

    .board {
        grid-template-columns: repeat(10, 24px);
        grid-template-rows: repeat(20, 24px);
    }

    .cell { width: 24px; height: 24px; }

    .side-panel {
        width: 100%;
        max-width: 300px;
    }

    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .stat-card {
        flex-direction: column;
        text-align: center;
        padding: 8px;
        gap: 4px;
    }

    .stat-icon { display: none; }

    .stat-value { font-size: 16px; }
    .stat-label { font-size: 9px; }
}