/* ============================================
   4D CHESS - DARK MODE STYLES
   ============================================ */

/* CSS Variables - Color Scheme */
:root {
    /* Backgrounds */
    --bg-primary: #0a0e27;
    --bg-secondary: #141933;
    --bg-tertiary: #1e2746;
    --bg-card: #1a1f3a;
    
    /* Accents */
    --accent-primary: #00d4ff;
    --accent-secondary: #7b2ff7;
    --accent-success: #00ff88;
    --accent-danger: #ff3366;
    --accent-warning: #ffaa00;
    
    /* Text */
    --text-primary: #ffffff;
    --text-secondary: #b4b4d4;
    --text-tertiary: #7878a3;
    
    /* Chess pieces */
    --piece-white: #fcf6e3;
    --piece-black: #818181;
    
    /* Board */
    --board-light: #ccccfc;
    --board-dark: #444464;
    
    /* Highlights */
    --highlight-move: #90ee90;
    --highlight-capture: #ff0000;
    --highlight-selected: #00b9ff;
    
    /* Dimensions */
    --header-height: 60px;
    --panel-width: 280px;
    --border-radius: 8px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
}

/* ============================================
   RESET & BASE
   ============================================ */

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow: hidden;
    height: 100vh;
}

/* ============================================
   HEADER BAR
   ============================================ */

.header-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-lg);
    height: var(--header-height);
    background: var(--bg-secondary);
    border-bottom: 2px solid var(--accent-primary);
    box-shadow: 0 4px 20px rgba(0, 212, 255, 0.2);
    gap: var(--spacing-md);
}

.header-buttons {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

.btn-tutorial,
.btn-feedback {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--border-radius);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    position: relative;
    overflow: hidden;
}

.btn-tutorial {
    background: linear-gradient(135deg, #00d4ff, #7b2ff7);
    color: var(--text-primary);
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.4);
    animation: shine 3s infinite;
}

.btn-tutorial::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(
        45deg,
        transparent,
        rgba(255, 255, 255, 0.3),
        transparent
    );
    transform: rotate(45deg);
    animation: shine-sweep 3s infinite;
}

@keyframes shine {
    0%, 100% {
        box-shadow: 0 4px 15px rgba(0, 212, 255, 0.4);
    }
    50% {
        box-shadow: 0 4px 25px rgba(0, 212, 255, 0.8), 0 0 30px rgba(0, 212, 255, 0.5);
    }
}

@keyframes shine-sweep {
    0% {
        transform: translateX(-100%) translateY(-100%) rotate(45deg);
    }
    50% {
        transform: translateX(100%) translateY(100%) rotate(45deg);
    }
    100% {
        transform: translateX(-100%) translateY(-100%) rotate(45deg);
    }
}

.btn-tutorial:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(0, 212, 255, 0.6);
}

.btn-feedback {
    background: #ff8800;
    color: var(--text-primary);
    box-shadow: 0 4px 15px rgba(255, 136, 0, 0.3);
}

.btn-feedback:hover {
    background: #ff9900;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 136, 0, 0.5);
}

.game-mode-selector {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
    flex: 1;
    justify-content: center;
}

.mode-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border: 2px solid transparent;
    border-radius: var(--border-radius);
    color: var(--text-secondary);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.mode-btn:hover {
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

.mode-btn.active {
    background: var(--accent-primary);
    color: var(--bg-primary);
    border-color: var(--accent-primary);
    box-shadow: 0 0 10px rgba(0, 212, 255, 0.4);
}

.mode-btn.active:hover {
    background: var(--accent-secondary);
    border-color: var(--accent-secondary);
}

.menu-btn, .settings-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--accent-primary);
    color: var(--text-primary);
    font-size: 20px;
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.3s ease;
}

.menu-btn:hover, .settings-btn:hover {
    background: var(--accent-primary);
    transform: scale(1.1);
}

.title {
    font-size: 24px;
    font-weight: bold;
    letter-spacing: 2px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.header-logo {
    width: 48px;
    height: 48px;
    object-fit: contain;
    display: inline-block;
    vertical-align: middle;
}

.turn-indicator {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--bg-tertiary);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    transition: all 0.3s ease;
}

.turn-indicator.white-turn {
    background: var(--bg-tertiary);
}

.turn-indicator.black-turn {
    background: #ffffff;
    border: 1px solid var(--accent-primary);
}

.turn-icon {
    font-size: 24px;
    display: inline-block;
    vertical-align: middle;
    line-height: 1;
    transition: color 0.3s ease;
}

.turn-indicator.white-turn .turn-icon {
    color: var(--text-secondary);
}

.turn-indicator.black-turn .turn-icon {
    color: #3b3f63; /* Dark blue-purple */
}

.turn-text {
    font-weight: 600;
    color: var(--text-secondary);
    transition: color 0.3s ease;
}

.turn-indicator.white-turn .turn-text {
    color: var(--text-secondary);
}

.turn-indicator.black-turn .turn-text {
    color: #3b3f63; /* Dark blue-purple */
}

.check-indicator {
    animation: pulse 1s infinite;
}

.check-text {
    color: var(--accent-danger);
    font-weight: bold;
    font-size: 18px;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* ============================================
   MAIN CONTAINER & LAYOUT
   ============================================ */

.main-container {
    display: flex;
    height: calc(100vh - var(--header-height));
}

.control-panel,
.nav-panel {
    width: var(--panel-width);
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    overflow-y: auto;
    overflow-x: hidden;
}

.control-panel {
    border-right: 1px solid var(--bg-tertiary);
}

.nav-panel {
    border-left: 1px solid var(--bg-tertiary);
}

/* Custom Scrollbar */
.control-panel::-webkit-scrollbar,
.nav-panel::-webkit-scrollbar {
    width: 8px;
}

.control-panel::-webkit-scrollbar-track,
.nav-panel::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

.control-panel::-webkit-scrollbar-thumb,
.nav-panel::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 4px;
}

.game-view {
    flex: 1;
    position: relative;
    background: var(--bg-primary);
}

#game-canvas {
    width: 100%;
    height: 100%;
    display: block;
}

/* ============================================
   NAVIGATION CONTROLS OVERLAY
   ============================================ */

.nav-controls-overlay {
    position: absolute;
    bottom: 15px;
    right: 15px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 1000;
    pointer-events: none; /* Allow clicks through container, but buttons capture them */
}

.nav-controls-overlay > * {
    pointer-events: auto; /* Re-enable pointer events for buttons */
}

.nav-control-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    align-items: center;
}

.nav-group-label {
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--accent-primary);
    margin-bottom: 2px;
    opacity: 0.9;
}

.nav-rotate-group .nav-group-label {
    color: var(--accent-secondary);
}

/* Freeze Button */
.nav-btn-freeze {
    background: linear-gradient(135deg, var(--accent-primary), #0099cc);
    border: 2px solid var(--accent-primary);
    color: white;
    padding: 8px 16px;
    border-radius: 10px;
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 70px;
}

.nav-btn-freeze:hover {
    background: linear-gradient(135deg, #00e5ff, var(--accent-primary));
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 212, 255, 0.5);
}

.nav-btn-freeze:active {
    transform: translateY(0);
    box-shadow: 0 2px 10px rgba(0, 212, 255, 0.3);
}

.nav-btn-freeze.frozen {
    background: linear-gradient(135deg, var(--accent-danger), #cc0033);
    border-color: var(--accent-danger);
    box-shadow: 0 4px 15px rgba(255, 51, 102, 0.3);
}

.nav-btn-freeze.frozen:hover {
    background: linear-gradient(135deg, #ff3366, var(--accent-danger));
    box-shadow: 0 6px 20px rgba(255, 51, 102, 0.5);
}

/* Arrow Pad Group */
.nav-pad-group {
    background: rgba(10, 14, 39, 0.85);
    backdrop-filter: blur(10px);
    border: 2px solid var(--accent-primary);
    border-radius: 12px;
    padding: 8px;
    box-shadow: 0 8px 32px rgba(0, 212, 255, 0.2);
}

.nav-pad-row {
    display: flex;
    gap: 6px;
    justify-content: center;
}

.nav-btn-arrow {
    width: 38px;
    height: 38px;
    background: linear-gradient(135deg, var(--accent-primary), #0099cc);
    border: 2px solid var(--accent-primary);
    border-radius: 8px;
    color: white;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.3);
}

.nav-btn-arrow:hover {
    background: linear-gradient(135deg, #00e5ff, var(--accent-primary));
    transform: scale(1.1);
    box-shadow: 0 6px 18px rgba(0, 212, 255, 0.5);
}

.nav-btn-arrow:active {
    transform: scale(0.95);
    box-shadow: 0 2px 8px rgba(0, 212, 255, 0.3);
}

.nav-btn-center {
    width: 38px;
    height: 38px;
    background: linear-gradient(135deg, var(--accent-secondary), #5a1cc7);
    border: 2px solid var(--accent-secondary);
    border-radius: 50%;
    color: white;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(123, 47, 247, 0.3);
}

.nav-btn-center:hover {
    background: linear-gradient(135deg, #8b3fff, var(--accent-secondary));
    transform: scale(1.1);
    box-shadow: 0 6px 18px rgba(123, 47, 247, 0.5);
}

.nav-btn-center:active {
    transform: scale(0.95);
}

/* Zoom Group */
.nav-zoom-group {
    flex-direction: row;
    gap: 8px;
}

.nav-btn-zoom {
    flex: 1;
    background: linear-gradient(135deg, var(--accent-primary), #0099cc);
    border: 2px solid var(--accent-primary);
    border-radius: 10px;
    color: white;
    padding: 8px 12px;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.3);
    min-width: 60px;
}

.nav-btn-zoom:hover {
    background: linear-gradient(135deg, #00e5ff, var(--accent-primary));
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(0, 212, 255, 0.5);
}

.nav-btn-zoom:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(0, 212, 255, 0.3);
}

.nav-btn-zoom .nav-label {
    font-size: 9px;
    font-weight: 500;
    opacity: 0.9;
}

/* Rotation Group (Sphere) */
.nav-rotate-group {
    background: rgba(10, 14, 39, 0.85);
    backdrop-filter: blur(10px);
    border: 2px solid var(--accent-secondary);
    border-radius: 12px;
    padding: 8px;
    box-shadow: 0 8px 32px rgba(123, 47, 247, 0.2);
}

.nav-rotate-row {
    display: flex;
    gap: 6px;
    justify-content: center;
}

.nav-btn-rotate {
    width: 38px;
    height: 38px;
    background: linear-gradient(135deg, var(--accent-secondary), #5a1cc7);
    border: 2px solid var(--accent-secondary);
    border-radius: 8px;
    color: white;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(123, 47, 247, 0.3);
}

.nav-btn-rotate:hover {
    background: linear-gradient(135deg, #8b3fff, var(--accent-secondary));
    transform: scale(1.1);
    box-shadow: 0 6px 18px rgba(123, 47, 247, 0.5);
}

.nav-btn-rotate:active {
    transform: scale(0.95);
    box-shadow: 0 2px 8px rgba(123, 47, 247, 0.3);
}

.nav-btn-center-small {
    width: 38px;
    height: 38px;
    background: linear-gradient(135deg, var(--accent-primary), #0099cc);
    border: 2px solid var(--accent-primary);
    border-radius: 50%;
    color: white;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.3);
}

.nav-btn-center-small:hover {
    background: linear-gradient(135deg, #00e5ff, var(--accent-primary));
    transform: scale(1.1);
    box-shadow: 0 6px 18px rgba(0, 212, 255, 0.5);
}

.nav-btn-center-small:active {
    transform: scale(0.95);
    box-shadow: 0 2px 8px rgba(0, 212, 255, 0.3);
}

/* Common styles */
.nav-icon {
    display: block;
    line-height: 1;
    user-select: none;
}

.nav-label {
    font-size: 11px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    user-select: none;
}

/* ============================================
   CARDS
   ============================================ */

.card {
    background: var(--bg-card);
    border: 1px solid var(--bg-tertiary);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.card h3 {
    font-size: 16px;
    margin-bottom: var(--spacing-md);
    color: var(--accent-primary);
    border-bottom: 1px solid var(--bg-tertiary);
    padding-bottom: var(--spacing-sm);
}

.card ul {
    list-style: none;
}

.card li {
    padding: var(--spacing-sm) 0;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
}

.card li span:last-child {
    color: var(--text-primary);
    font-weight: 600;
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: var(--text-primary);
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 212, 255, 0.5);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--accent-primary);
}

.btn-secondary:hover {
    background: var(--accent-primary);
    color: var(--bg-primary);
}

.btn-large {
    width: 100%;
    padding: 15px;
    font-size: 16px;
    margin-bottom: var(--spacing-md);
}

.new-game-icon {
    font-size: 20px;
    line-height: 1.2;
    display: inline-block;
    vertical-align: baseline;
    margin-right: 8px;
    font-weight: normal;
}

.btn-block {
    width: 100%;
    margin-bottom: var(--spacing-sm);
}

.btn-group {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.btn-group .btn {
    flex: 1;
}

.btn-nav {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--accent-primary);
    padding: 8px 12px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 12px;
    transition: all 0.2s ease;
}

.btn-nav:hover {
    background: var(--accent-primary);
    color: var(--bg-primary);
}

/* ============================================
   STATISTICS
   ============================================ */

.stat-row {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
    color: var(--text-secondary);
}

.stat-value {
    color: var(--accent-success);
    font-weight: bold;
}

/* ============================================
   MOVE HISTORY
   ============================================ */

.move-list {
    max-height: 300px;
    overflow-y: auto;
    padding-right: var(--spacing-sm);
}

.move-list::-webkit-scrollbar {
    width: 6px;
}

.move-list::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: 3px;
}

.move-list::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 3px;
}

.move-list::-webkit-scrollbar-thumb:hover {
    background: var(--accent-secondary);
}

.move-item {
    padding: var(--spacing-sm);
    margin-bottom: 4px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    font-size: 12px;
    color: var(--text-secondary);
    font-family: 'Courier New', monospace;
}

.move-item:hover {
    background: var(--bg-primary);
    color: var(--text-primary);
}

/* ============================================
   NAVIGATION CONTROLS
   ============================================ */

.axis-control {
    margin-bottom: var(--spacing-lg);
}

.axis-control label {
    display: block;
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.slider {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--bg-tertiary);
    outline: none;
    margin-bottom: var(--spacing-sm);
    -webkit-appearance: none;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent-primary);
    cursor: pointer;
    box-shadow: 0 0 10px rgba(0, 212, 255, 0.5);
}

.slider::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent-primary);
    cursor: pointer;
    border: none;
    box-shadow: 0 0 10px rgba(0, 212, 255, 0.5);
}

.axis-buttons {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-sm);
}

.axis-value {
    font-weight: bold;
    color: var(--accent-primary);
    font-family: 'Courier New', monospace;
}

/* ============================================
   GIZMO CONTAINER
   ============================================ */

.gizmo-container {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: var(--border-radius);
    display: flex;
    flex-direction: column;
    align-items: center;
}

#axes-gizmo-canvas {
    width: 200px;
    height: 200px;
    background: var(--bg-secondary);
    border: 1px solid var(--accent-primary);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-md);
}

.gizmo-legend {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.gizmo-legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 11px;
    color: var(--text-secondary);
}

.gizmo-color {
    display: inline-block;
    width: 12px;
    height: 12px;
    border-radius: 2px;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* ============================================
   PIECE INFO CONTAINER
   ============================================ */

.piece-info-container {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--accent-primary);
    border-radius: var(--border-radius);
    max-height: 400px;
    display: flex;
    flex-direction: column;
}

.piece-info-header {
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--bg-secondary);
    color: var(--accent-primary);
    font-size: 16px;
}

.piece-info-position {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
    font-size: 12px;
    font-family: 'Courier New', monospace;
    line-height: 1.6;
}

.piece-info-position .position-label {
    margin-bottom: 4px;
    color: var(--text-secondary);
}

.piece-info-position .position-coords {
    font-family: 'Courier New', monospace;
}

.piece-info-position .coord-item {
    color: var(--text-secondary);
    margin-right: 8px;
}

.piece-info-position .coord-item span {
    color: var(--accent-primary);
    font-weight: bold;
    margin-left: 2px;
}

.piece-info-moves-header {
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
    font-size: 13px;
    font-weight: bold;
}

.piece-info-moves-list {
    overflow-y: auto;
    max-height: 250px;
    padding-right: var(--spacing-sm);
}

.piece-info-moves-list::-webkit-scrollbar {
    width: 6px;
}

.piece-info-moves-list::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: 3px;
}

.piece-info-moves-list::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 3px;
}

.piece-info-moves-list::-webkit-scrollbar-thumb:hover {
    background: var(--accent-secondary);
}

.piece-move-item {
    padding: 4px var(--spacing-sm);
    margin-bottom: 4px;
    background: var(--bg-secondary);
    border-radius: 4px;
    font-size: 11px;
    font-family: 'Courier New', monospace;
    color: var(--text-secondary);
    border-left: 2px solid var(--accent-primary);
}

.piece-move-item.clickable {
    cursor: pointer;
    transition: all 0.2s ease;
}

.piece-move-item.clickable:hover {
    background: var(--bg-card);
    color: var(--text-primary);
    transform: translateX(4px);
    box-shadow: 0 2px 4px rgba(0, 212, 255, 0.2);
}

.piece-move-item.clickable:active {
    transform: translateX(2px);
    box-shadow: 0 1px 2px rgba(0, 212, 255, 0.3);
}

.piece-move-item.capture {
    border-left-color: var(--accent-danger);
    background: rgba(255, 51, 102, 0.1);
}

.piece-move-item.capture.clickable:hover {
    background: rgba(255, 51, 102, 0.25);
    box-shadow: 0 2px 4px rgba(255, 51, 102, 0.3);
}

.piece-move-item:not(.clickable):hover {
    background: var(--bg-card);
    color: var(--text-primary);
}

/* ============================================
   TUTORIAL SECTION
   ============================================ */

.tutorial-card {
    margin-top: var(--spacing-lg);
}

.tutorial-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-radius: var(--border-radius);
}

.btn-nav-small {
    background: var(--bg-secondary);
    border: 1px solid var(--accent-primary);
    color: var(--text-primary);
    width: 32px;
    height: 32px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-nav-small:hover {
    background: var(--accent-primary);
    transform: scale(1.1);
}

.tutorial-page-indicator {
    font-weight: bold;
    color: var(--accent-primary);
    font-family: 'Courier New', monospace;
    font-size: 14px;
}

.tutorial-viewer {
    position: relative;
    width: 100%;
    height: 200px;
    background: var(--bg-secondary);
    border: 1px solid var(--accent-primary);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-md);
    overflow: hidden;
}

#tutorial-piece-canvas {
    width: 100%;
    height: 100%;
    display: block;
}

.tutorial-controls {
    position: absolute;
    bottom: 8px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.7);
    padding: 4px 12px;
    border-radius: 12px;
    pointer-events: none;
}

.tutorial-hint {
    font-size: 10px;
    color: var(--text-secondary);
    white-space: nowrap;
}

.tutorial-piece-name {
    font-size: 18px;
    color: var(--accent-primary);
    margin-bottom: var(--spacing-sm);
    text-align: center;
    font-weight: bold;
}

.tutorial-description {
    font-size: 12px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-radius: var(--border-radius);
    min-height: 50px; /* Ensure it has visible height */
    display: block !important; /* Force display */
}

.tutorial-description strong {
    color: var(--text-primary);
}

.tutorial-examples {
    font-size: 11px;
    color: var(--text-tertiary);
    min-height: 30px; /* Ensure it has visible height */
    display: block !important; /* Force display */
}

.tutorial-example {
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-left: 3px solid var(--accent-primary);
    border-radius: 4px;
}

.tutorial-example-title {
    font-weight: bold;
    color: var(--accent-primary);
    margin-bottom: 4px;
}

.tutorial-example-text {
    color: var(--text-secondary);
    line-height: 1.5;
}

/* ============================================
   VIEW OPTIONS
   ============================================ */

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) 0;
    cursor: pointer;
    color: var(--text-secondary);
    transition: color 0.2s ease;
}

.checkbox-label:hover {
    color: var(--text-primary);
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent-primary);
}

/* ============================================
   KEYBOARD SHORTCUTS
   ============================================ */

.shortcut-list {
    font-size: 12px;
}

.shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 0;
    color: var(--text-tertiary);
}

.shortcut-item .key {
    background: var(--bg-tertiary);
    padding: 4px 8px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent-primary);
    font-weight: bold;
}

/* ============================================
   LOADING SCREEN
   ============================================ */

.loading-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.loading-content {
    text-align: center;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid var(--bg-tertiary);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-lg);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-content h2 {
    font-size: 24px;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.loading-content p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* ============================================
   MODAL
   ============================================ */

.modal {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 14, 39, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 999;
}

.modal-content {
    background: var(--bg-card);
    border: 2px solid var(--accent-primary);
    border-radius: var(--border-radius);
    padding: calc(var(--spacing-lg) * 2);
    text-align: center;
    max-width: 400px;
    box-shadow: 0 10px 40px rgba(0, 212, 255, 0.3);
}

.modal-content h2 {
    font-size: 32px;
    margin-bottom: var(--spacing-md);
    color: var(--accent-primary);
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    font-size: 16px;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 1400px) {
    :root {
        --panel-width: 240px;
    }
}

@media (max-width: 1200px) {
    .control-panel,
    .nav-panel {
        position: absolute;
        z-index: 100;
        height: calc(100vh - var(--header-height));
        transition: transform 0.3s ease;
    }
    
    .control-panel {
        left: 0;
        transform: translateX(-100%);
    }
    
    .nav-panel {
        right: 0;
        transform: translateX(100%);
    }
    
    .control-panel.visible {
        transform: translateX(0);
    }
    
    .nav-panel.visible {
        transform: translateX(0);
    }
}

/* ============================================
   ANIMATIONS
   ============================================ */

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card {
    animation: fadeIn 0.5s ease;
}

/* ============================================
   UTILITIES
   ============================================ */

/* ============================================
   TUTORIAL MODAL
   ============================================ */

.tutorial-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 14, 39, 0.98);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    animation: fadeIn 0.3s ease;
}

.tutorial-modal-content {
    position: relative;
    width: 90%;
    max-width: 900px;
    max-height: 85vh;
    background: var(--bg-card);
    border: 2px solid var(--accent-primary);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: 0 10px 40px rgba(0, 212, 255, 0.3);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.tutorial-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    width: 40px;
    height: 40px;
    background: var(--bg-tertiary);
    border: 2px solid var(--accent-primary);
    border-radius: 50%;
    color: var(--text-primary);
    font-size: 28px;
    line-height: 1;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: center;
}

.tutorial-close:hover {
    background: var(--accent-danger);
    border-color: var(--accent-danger);
    transform: rotate(90deg) scale(1.1);
}

.tutorial-nav-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.tutorial-nav-arrow {
    width: 50px;
    height: 50px;
    background: var(--bg-tertiary);
    border: 2px solid var(--accent-primary);
    border-radius: 50%;
    color: var(--text-primary);
    font-size: 24px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.tutorial-nav-arrow:hover {
    background: var(--accent-primary);
    color: var(--bg-primary);
    transform: scale(1.1);
}

.tutorial-nav-arrow:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none;
}

.tutorial-nav-arrow:disabled:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transform: none;
}

.tutorial-content {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-md);
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    min-height: 400px;
    max-height: calc(85vh - 200px);
}

.tutorial-content::-webkit-scrollbar {
    width: 8px;
}

.tutorial-content::-webkit-scrollbar-track {
    background: var(--bg-primary);
    border-radius: 4px;
}

.tutorial-content::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 4px;
}

.tutorial-content::-webkit-scrollbar-thumb:hover {
    background: var(--accent-secondary);
}

.tutorial-page {
    display: none;
}

.tutorial-page.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

.tutorial-page h2 {
    color: var(--accent-primary);
    font-size: 28px;
    margin-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--accent-primary);
    padding-bottom: var(--spacing-sm);
}

.tutorial-page h3 {
    color: var(--accent-secondary);
    font-size: 20px;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.tutorial-page p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
    font-size: 15px;
}

.tutorial-page ul,
.tutorial-page ol {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.tutorial-page li {
    margin-bottom: var(--spacing-sm);
}

.tutorial-page code {
    background: var(--bg-tertiary);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent-primary);
    font-size: 14px;
}

.tutorial-page strong {
    color: var(--text-primary);
    font-weight: 600;
}

.tutorial-modal-page-indicator {
    text-align: center;
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm);
    font-size: 14px;
    color: var(--text-secondary);
    font-family: 'Courier New', monospace;
}

.tutorial-modal-page-indicator span {
    color: var(--accent-primary);
    font-weight: bold;
}

.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }