static/css/style.css

/* ========================================
   CSS Variables & Theme Definitions
======================================== */
:root {
    /* Default Dark Theme */
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f3460;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --accent-primary: #e94560;
    --accent-secondary: #0f3460;
    --board-light: #eeeed2;
    --board-dark: #769656;
    --highlight-move: rgba(255, 255, 0, 0.4);
    --highlight-selected: rgba(20, 85, 30, 0.5);
    --highlight-legal: rgba(0, 0, 0, 0.1);
    --highlight-capture: rgba(255, 0, 0, 0.4);
    --check-color: #ff0000;
    --border-color: #333;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --modal-bg: rgba(0, 0, 0, 0.8);
}

/* Light Theme */
.theme-light {
    --bg-primary: #f5f5f5;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e0e0e0;
    --text-primary: #1a1a1a;
    --text-secondary: #666666;
    --accent-primary: #2196f3;
    --accent-secondary: #1976d2;
    --border-color: #ddd;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

/* Forest Theme */
.theme-forest {
    --bg-primary: #1b2d1b;
    --bg-secondary: #2d4a2d;
    --bg-tertiary: #3d6b3d;
    --text-primary: #e8f5e9;
    --text-secondary: #a5d6a7;
    --accent-primary: #4caf50;
    --accent-secondary: #2e7d32;
    --board-light: #c8e6c9;
    --board-dark: #388e3c;
    --border-color: #2e7d32;
}

/* Ocean Theme */
.theme-ocean {
    --bg-primary: #0d1b2a;
    --bg-secondary: #1b263b;
    --bg-tertiary: #415a77;
    --text-primary: #e0e1dd;
    --text-secondary: #778da9;
    --accent-primary: #00b4d8;
    --accent-secondary: #0077b6;
    --board-light: #caf0f8;
    --board-dark: #0077b6;
    --border-color: #0077b6;
}

/* Sunset Theme */
.theme-sunset {
    --bg-primary: #2d132c;
    --bg-secondary: #801336;
    --bg-tertiary: #c72c41;
    --text-primary: #fff5e4;
    --text-secondary: #ee6f57;
    --accent-primary: #ee6f57;
    --accent-secondary: #c72c41;
    --board-light: #ffeaa7;
    --board-dark: #d63031;
    --border-color: #c72c41;
}

/* Midnight Theme */
.theme-midnight {
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --text-primary: #ffffff;
    --text-secondary: #888888;
    --accent-primary: #6c5ce7;
    --accent-secondary: #5541d7;
    --board-light: #b8b8b8;
    --board-dark: #4a4a4a;
    --border-color: #333;
}

/* Cream Theme */
.theme-cream {
    --bg-primary: #f5f0e1;
    --bg-secondary: #fffef9;
    --bg-tertiary: #e8e0cc;
    --text-primary: #2c2c2c;
    --text-secondary: #666666;
    --accent-primary: #c9a959;
    --accent-secondary: #8b7355;
    --board-light: #f0d9b5;
    --board-dark: #b58863;
    --border-color: #c9a959;
}

/* Lavender Theme */
.theme-lavender {
    --bg-primary: #2d2540;
    --bg-secondary: #3d3356;
    --bg-tertiary: #5a4f7a;
    --text-primary: #e8e0f0;
    --text-secondary: #b8a8d0;
    --accent-primary: #9b59b6;
    --accent-secondary: #8e44ad;
    --board-light: #e8d5f0;
    --board-dark: #9b59b6;
    --border-color: #8e44ad;
}

/* Mint Theme */
.theme-mint {
    --bg-primary: #1a332e;
    --bg-secondary: #2a4a44;
    --bg-tertiary: #3a6a60;
    --text-primary: #e0f2ef;
    --text-secondary: #98d4c8;
    --accent-primary: #1abc9c;
    --accent-secondary: #16a085;
    --board-light: #a8e6cf;
    --board-dark: #20b2aa;
    --border-color: #16a085;
}

/* Slate Theme */
.theme-slate {
    --bg-primary: #2c3e50;
    --bg-secondary: #34495e;
    --bg-tertiary: #4a6278;
    --text-primary: #ecf0f1;
    --text-secondary: #95a5a6;
    --accent-primary: #3498db;
    --accent-secondary: #2980b9;
    --board-light: #bdc3c7;
    --board-dark: #7f8c8d;
    --border-color: #2980b9;
}

/* ========================================
   Rainbow Theme (Special) - Only Board Animates
======================================== */
.theme-rainbow {
    /* Same as Dark Theme */
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f3460;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --accent-primary: #e94560;
    --accent-secondary: #0f3460;
    --border-color: #333;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --modal-bg: rgba(0, 0, 0, 0.8);
    --highlight-move: rgba(255, 255, 0, 0.4);
    --highlight-selected: rgba(20, 85, 30, 0.5);
    --highlight-legal: rgba(0, 0, 0, 0.1);
    --highlight-capture: rgba(255, 0, 0, 0.4);
    --check-color: #ff0000;
}

/* Rainbow animated board glow */
.theme-rainbow .chessboard {
    animation: rainbow-glow 8s ease infinite;
}

@keyframes rainbow-glow {
    0%, 100% { 
        box-shadow: 0 0 30px #ff6b6b, 0 0 60px #ff6b6b, inset 0 0 20px rgba(255, 107, 107, 0.1);
        border-color: #ff6b6b;
    }
    14% { 
        box-shadow: 0 0 30px #feca57, 0 0 60px #feca57, inset 0 0 20px rgba(254, 202, 87, 0.1);
        border-color: #feca57;
    }
    28% { 
        box-shadow: 0 0 30px #48dbfb, 0 0 60px #48dbfb, inset 0 0 20px rgba(72, 219, 251, 0.1);
        border-color: #48dbfb;
    }
    42% { 
        box-shadow: 0 0 30px #1dd1a1, 0 0 60px #1dd1a1, inset 0 0 20px rgba(29, 209, 161, 0.1);
        border-color: #1dd1a1;
    }
    56% { 
        box-shadow: 0 0 30px #5f27cd, 0 0 60px #5f27cd, inset 0 0 20px rgba(95, 39, 205, 0.1);
        border-color: #5f27cd;
    }
    70% { 
        box-shadow: 0 0 30px #ff9ff3, 0 0 60px #ff9ff3, inset 0 0 20px rgba(255, 159, 243, 0.1);
        border-color: #ff9ff3;
    }
    84% { 
        box-shadow: 0 0 30px #00d2d3, 0 0 60px #00d2d3, inset 0 0 20px rgba(0, 210, 211, 0.1);
        border-color: #00d2d3;
    }
}

/* Rainbow light squares */
.theme-rainbow .board-square.light {
    animation: rainbow-light-square 6s ease infinite;
}

@keyframes rainbow-light-square {
    0%, 100% { background-color: #ffe6e6; }
    14% { background-color: #fff8e6; }
    28% { background-color: #e6f9ff; }
    42% { background-color: #e6fff5; }
    56% { background-color: #f3e6ff; }
    70% { background-color: #ffe6fb; }
    84% { background-color: #e6ffff; }
}

/* Rainbow dark squares */
.theme-rainbow .board-square.dark {
    animation: rainbow-dark-square 6s ease infinite;
}

@keyframes rainbow-dark-square {
    0%, 100% { background-color: #ff6b6b; }
    14% { background-color: #feca57; }
    28% { background-color: #48dbfb; }
    42% { background-color: #1dd1a1; }
    56% { background-color: #5f27cd; }
    70% { background-color: #ff9ff3; }
    84% { background-color: #00d2d3; }
}

/* Coordinate labels for rainbow theme */
.theme-rainbow .board-square.light .coord-file,
.theme-rainbow .board-square.light .coord-rank {
    animation: rainbow-coord-dark 6s ease infinite;
}

@keyframes rainbow-coord-dark {
    0%, 100% { color: #cc5555; }
    14% { color: #cca044; }
    28% { color: #3ab0c9; }
    42% { color: #17a880; }
    56% { color: #4c1fa3; }
    70% { color: #cc7fc2; }
    84% { color: #00a8a9; }
}

.theme-rainbow .board-square.dark .coord-file,
.theme-rainbow .board-square.dark .coord-rank {
    color: #fff;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

/* Rainbow check ring */
.theme-rainbow .check-ring {
    animation: rainbow-check-ring 6s ease infinite, check-pulse 1.5s ease-in-out infinite;
}

@keyframes rainbow-check-ring {
    0%, 100% { 
        border-color: #ff0000;
        box-shadow: 0 0 20px #ff0000;
    }
    14% { 
        border-color: #ff6600;
        box-shadow: 0 0 20px #ff6600;
    }
    28% { 
        border-color: #ff00ff;
        box-shadow: 0 0 20px #ff00ff;
    }
    42% { 
        border-color: #ff0066;
        box-shadow: 0 0 20px #ff0066;
    }
    56% { 
        border-color: #ff3300;
        box-shadow: 0 0 20px #ff3300;
    }
    70% { 
        border-color: #ff0099;
        box-shadow: 0 0 20px #ff0099;
    }
    84% { 
        border-color: #ff3366;
        box-shadow: 0 0 20px #ff3366;
    }
}

/* Rainbow last move highlight */
.theme-rainbow .board-square.last-move {
    animation: rainbow-last-move 6s ease infinite !important;
}

@keyframes rainbow-last-move {
    0%, 100% { background-color: rgba(255, 107, 107, 0.5) !important; }
    14% { background-color: rgba(254, 202, 87, 0.5) !important; }
    28% { background-color: rgba(72, 219, 251, 0.5) !important; }
    42% { background-color: rgba(29, 209, 161, 0.5) !important; }
    56% { background-color: rgba(95, 39, 205, 0.5) !important; }
    70% { background-color: rgba(255, 159, 243, 0.5) !important; }
    84% { background-color: rgba(0, 210, 211, 0.5) !important; }
}

/* Rainbow selected square */
.theme-rainbow .board-square.selected {
    animation: rainbow-selected 6s ease infinite !important;
}

@keyframes rainbow-selected {
    0%, 100% { background-color: rgba(255, 107, 107, 0.6) !important; }
    14% { background-color: rgba(254, 202, 87, 0.6) !important; }
    28% { background-color: rgba(72, 219, 251, 0.6) !important; }
    42% { background-color: rgba(29, 209, 161, 0.6) !important; }
    56% { background-color: rgba(95, 39, 205, 0.6) !important; }
    70% { background-color: rgba(255, 159, 243, 0.6) !important; }
    84% { background-color: rgba(0, 210, 211, 0.6) !important; }
}

/* Rainbow legal move dots */
.theme-rainbow .board-square.legal-move::after {
    animation: rainbow-legal-dot 6s ease infinite;
}

@keyframes rainbow-legal-dot {
    0%, 100% { background: rgba(255, 107, 107, 0.5); }
    14% { background: rgba(254, 202, 87, 0.5); }
    28% { background: rgba(72, 219, 251, 0.5); }
    42% { background: rgba(29, 209, 161, 0.5); }
    56% { background: rgba(95, 39, 205, 0.5); }
    70% { background: rgba(255, 159, 243, 0.5); }
    84% { background: rgba(0, 210, 211, 0.5); }
}

/* Rainbow legal capture rings */
.theme-rainbow .board-square.legal-capture::after {
    animation: rainbow-capture-ring 6s ease infinite;
}

@keyframes rainbow-capture-ring {
    0%, 100% { border-color: rgba(255, 107, 107, 0.8); }
    14% { border-color: rgba(254, 202, 87, 0.8); }
    28% { border-color: rgba(72, 219, 251, 0.8); }
    42% { border-color: rgba(29, 209, 161, 0.8); }
    56% { border-color: rgba(95, 39, 205, 0.8); }
    70% { border-color: rgba(255, 159, 243, 0.8); }
    84% { border-color: rgba(0, 210, 211, 0.8); }
}

/* Rainbow theme preview in dropdown */
.rainbow-preview { 
    background: linear-gradient(90deg, #ff6b6b, #feca57, #1dd1a1, #48dbfb, #5f27cd, #ff9ff3);
    animation: rainbow-spin 2s linear infinite;
}

@keyframes rainbow-spin {
    0% { filter: hue-rotate(0deg); }
    100% { filter: hue-rotate(360deg); }
}

/* ========================================
   Reset & Base Styles
======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    height: 100%;
    font-family: 'Roboto', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    overflow-x: hidden;
}

.hidden {
    display: none !important;
}

/* ========================================
   Loading Screen
======================================== */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-primary);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.loader {
    text-align: center;
}

.chess-piece-loader {
    font-size: 80px;
    animation: bounce 1s ease infinite;
    color: var(--accent-primary);
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

.loader p {
    margin-top: 20px;
    font-size: 18px;
    color: var(--text-secondary);
}

/* ========================================
   App Container
======================================== */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ========================================
   Header
======================================== */
.header {
    background: var(--bg-secondary);
    padding: 15px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 2px 10px var(--shadow-color);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 36px;
    color: var(--accent-primary);
}

.logo-text {
    font-family: 'Playfair Display', serif;
    font-size: 28px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-primary), var(--text-primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 15px;
}

.theme-selector {
    position: relative;
}

.theme-btn, .sound-btn {
    background: var(--bg-tertiary);
    border: none;
    color: var(--text-primary);
    padding: 10px 15px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.theme-btn:hover, .sound-btn:hover {
    background: var(--accent-primary);
    transform: translateY(-2px);
}

.theme-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 10px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 10px;
    min-width: 180px;
    box-shadow: 0 10px 30px var(--shadow-color);
    z-index: 1000;
    max-height: 400px;
    overflow-y: auto;
}

.theme-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.theme-option:hover {
    background: var(--bg-tertiary);
}

.theme-option.special {
    border: 1px solid var(--accent-primary);
    background: linear-gradient(90deg, rgba(255,107,107,0.1), rgba(78,205,196,0.1));
}

.theme-preview {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
}

.dark-preview { background: linear-gradient(135deg, #1a1a2e, #e94560); }
.light-preview { background: linear-gradient(135deg, #f5f5f5, #2196f3); }
.forest-preview { background: linear-gradient(135deg, #1b2d1b, #4caf50); }
.ocean-preview { background: linear-gradient(135deg, #0d1b2a, #00b4d8); }
.sunset-preview { background: linear-gradient(135deg, #2d132c, #ee6f57); }
.midnight-preview { background: linear-gradient(135deg, #0a0a0a, #6c5ce7); }
.cream-preview { background: linear-gradient(135deg, #f5f0e1, #c9a959); }
.lavender-preview { background: linear-gradient(135deg, #2d2540, #9b59b6); }
.mint-preview { background: linear-gradient(135deg, #1a332e, #1abc9c); }
.slate-preview { background: linear-gradient(135deg, #2c3e50, #3498db); }

/* ========================================
   Screens
======================================== */
.screen {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

/* ========================================
   Lobby Screen
======================================== */
.lobby-container {
    max-width: 900px;
    width: 100%;
    text-align: center;
}

.lobby-title {
    font-family: 'Playfair Display', serif;
    font-size: 48px;
    margin-bottom: 10px;
    background: linear-gradient(135deg, var(--accent-primary), var(--text-primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.lobby-subtitle {
    color: var(--text-secondary);
    font-size: 18px;
    margin-bottom: 40px;
}

.username-section {
    margin-bottom: 40px;
}

.username-section label {
    display: block;
    margin-bottom: 10px;
    font-weight: 500;
    color: var(--text-secondary);
}

.username-section input {
    width: 100%;
    max-width: 400px;
    padding: 15px 20px;
    font-size: 18px;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    text-align: center;
    transition: all 0.3s ease;
}

.username-section input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 20px rgba(233, 69, 96, 0.2);
}

.lobby-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.option-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 30px;
    transition: all 0.3s ease;
}

.option-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px var(--shadow-color);
    border-color: var(--accent-primary);
}

.option-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto 20px;
    font-size: 36px;
    color: white;
}

.option-card h3 {
    font-size: 24px;
    margin-bottom: 10px;
}

.option-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.time-control-section {
    margin-bottom: 20px;
}

.time-control-section label {
    display: block;
    margin-bottom: 10px;
    font-weight: 500;
    color: var(--text-secondary);
}

.time-options {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
}

.time-btn {
    padding: 10px 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.time-btn:hover, .time-btn.active {
    border-color: var(--accent-primary);
    background: var(--accent-primary);
    color: white;
}

.room-code-section input {
    width: 100%;
    padding: 15px;
    font-size: 24px;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 5px;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    margin-bottom: 20px;
}

.room-code-section input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

/* ========================================
   Buttons
======================================== */
.btn {
    padding: 15px 30px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    transition: all 0.3s ease;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(233, 69, 96, 0.4);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

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

.btn-text {
    background: transparent;
    color: var(--accent-primary);
    padding: 10px;
}

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

.btn-danger {
    background: #e74c3c;
    color: white;
}

.btn-danger:hover {
    background: #c0392b;
}

/* ========================================
   Available Rooms
======================================== */
.available-rooms {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 30px;
}

.available-rooms h3 {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 20px;
}

.rooms-list {
    max-height: 200px;
    overflow-y: auto;
    margin-bottom: 15px;
}

.room-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: var(--bg-tertiary);
    border-radius: 10px;
    margin-bottom: 10px;
    transition: all 0.3s ease;
}

.room-item:hover {
    transform: translateX(5px);
    border-left: 3px solid var(--accent-primary);
}

.room-info {
    text-align: left;
}

.room-host {
    font-weight: 600;
}

.room-time {
    font-size: 14px;
    color: var(--text-secondary);
}

.no-rooms {
    color: var(--text-secondary);
    font-style: italic;
}

/* ========================================
   Waiting Screen
======================================== */
.waiting-container {
    text-align: center;
    max-width: 500px;
}

.waiting-animation {
    margin-bottom: 30px;
}

.chess-pieces-animation {
    display: flex;
    justify-content: center;
    gap: 10px;
    font-size: 48px;
}

.chess-pieces-animation span {
    animation: float 2s ease-in-out infinite;
    color: var(--accent-primary);
}

.chess-pieces-animation span:nth-child(1) { animation-delay: 0s; }
.chess-pieces-animation span:nth-child(2) { animation-delay: 0.2s; }
.chess-pieces-animation span:nth-child(3) { animation-delay: 0.4s; }
.chess-pieces-animation span:nth-child(4) { animation-delay: 0.6s; }
.chess-pieces-animation span:nth-child(5) { animation-delay: 0.8s; }
.chess-pieces-animation span:nth-child(6) { animation-delay: 1s; }

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

.waiting-container h2 {
    font-size: 32px;
    margin-bottom: 15px;
}

.waiting-container p {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.room-code-display {
    display: inline-flex;
    align-items: center;
    gap: 15px;
    background: var(--bg-secondary);
    padding: 20px 30px;
    border-radius: 15px;
    border: 2px dashed var(--accent-primary);
    margin-bottom: 20px;
}

.room-code-display span {
    font-size: 36px;
    font-weight: 700;
    letter-spacing: 5px;
    color: var(--accent-primary);
}

.copy-btn {
    background: var(--accent-primary);
    border: none;
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 20px;
    transition: all 0.3s ease;
}

.copy-btn:hover {
    transform: scale(1.1);
}

.waiting-info {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

/* ========================================
   Game Screen
======================================== */
.game-screen {
    display: flex;
    gap: 30px;
    padding: 20px;
    justify-content: center;
    align-items: flex-start;
}

.game-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

/* ========================================
   Player Info
======================================== */
.player-info {
    display: flex;
    align-items: center;
    gap: 15px;
    background: var(--bg-secondary);
    padding: 15px 25px;
    border-radius: 15px;
    min-width: 350px;
    border: 1px solid var(--border-color);
}

.player-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
}

.opponent-avatar {
    background: linear-gradient(135deg, #333, #555);
    color: white;
}

.self-avatar {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: white;
}

.player-details {
    flex: 1;
}

.player-name {
    display: block;
    font-weight: 600;
    font-size: 18px;
}

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

.player-timer {
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--bg-tertiary);
    padding: 10px 20px;
    border-radius: 10px;
    font-size: 24px;
    font-weight: 700;
    font-family: 'Roboto Mono', monospace;
}

.player-timer.low-time {
    background: #e74c3c;
    color: white;
    animation: pulse-warning 1s ease infinite;
}

@keyframes pulse-warning {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

/* ========================================
   Board Wrapper
======================================== */
.board-wrapper {
    display: flex;
    align-items: center;
    gap: 20px;
}

.captured-pieces {
    width: 50px;
    display: flex;
    flex-direction: column;
    gap: 5px;
    font-size: 24px;
}

.board-container {
    position: relative;
}

/* ========================================
   Chess Board
======================================== */
.chessboard {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    width: 560px;
    height: 560px;
    border: 4px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 20px 60px var(--shadow-color);
}

.board-square {
    width: 70px;
    height: 70px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 56px;
    cursor: pointer;
    position: relative;
    transition: background-color 0.2s ease;
    user-select: none;
}

.board-square.light {
    background-color: var(--board-light);
}

.board-square.dark {
    background-color: var(--board-dark);
}

.board-square .piece {
    cursor: grab;
    transition: transform 0.1s ease;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.board-square .piece:active {
    cursor: grabbing;
}

.board-square.selected {
    background-color: var(--highlight-selected) !important;
}

.board-square.last-move {
    background-color: var(--highlight-move) !important;
}

.board-square.legal-move::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 24px;
    background: var(--highlight-legal);
    border-radius: 50%;
}

.board-square.legal-capture::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    border: 5px solid var(--highlight-capture);
    border-radius: 50%;
    box-sizing: border-box;
}

.board-square.can-move {
    cursor: pointer;
}

/* ========================================
   Coordinate Labels
======================================== */
.board-square .coord-file {
    position: absolute;
    bottom: 2px;
    right: 4px;
    font-size: 12px;
    font-weight: 600;
    opacity: 0.7;
}

.board-square .coord-rank {
    position: absolute;
    top: 2px;
    left: 4px;
    font-size: 12px;
    font-weight: 600;
    opacity: 0.7;
}

.board-square.light .coord-file,
.board-square.light .coord-rank {
    color: var(--board-dark);
}

.board-square.dark .coord-file,
.board-square.dark .coord-rank {
    color: var(--board-light);
}

/* ========================================
   Check Indicator Ring
======================================== */
.check-ring {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    border: 4px solid var(--check-color);
    border-radius: 50%;
    animation: check-pulse 1.5s ease-in-out infinite;
    pointer-events: none;
}

@keyframes check-pulse {
    0%, 100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
        box-shadow: 0 0 20px var(--check-color);
    }
    50% {
        opacity: 0.5;
        transform: translate(-50%, -50%) scale(1.15);
        box-shadow: 0 0 40px var(--check-color);
    }
}

/* ========================================
   Game Controls
======================================== */
.game-controls {
    display: flex;
    gap: 15px;
}

.control-btn {
    width: 50px;
    height: 50px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.control-btn:hover {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
    transform: translateY(-3px);
}

.chat-badge {
    position: absolute;
    top: -5px;
    right: -5px;
    background: #e74c3c;
    color: white;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    font-size: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* ========================================
   Side Panel
======================================== */
.side-panel {
    width: 300px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.move-history-panel,
.chat-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    padding: 20px;
}

.move-history-panel h3,
.chat-panel h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.move-history {
    max-height: 200px;
    overflow-y: auto;
    font-family: 'Roboto Mono', monospace;
}

.move-row {
    display: flex;
    gap: 10px;
    padding: 8px;
    border-radius: 5px;
}

.move-row:nth-child(odd) {
    background: var(--bg-tertiary);
}

.move-number {
    width: 30px;
    color: var(--text-secondary);
}

.move-white,
.move-black {
    flex: 1;
    cursor: pointer;
    padding: 2px 5px;
    border-radius: 3px;
    transition: background 0.2s ease;
}

.move-white:hover,
.move-black:hover {
    background: var(--accent-primary);
    color: white;
}

/* ========================================
   Chat
======================================== */
.chat-messages {
    height: 200px;
    overflow-y: auto;
    margin-bottom: 15px;
    padding: 10px;
    background: var(--bg-tertiary);
    border-radius: 10px;
}

.chat-message {
    margin-bottom: 10px;
    padding: 8px 12px;
    background: var(--bg-secondary);
    border-radius: 8px;
}

.chat-message .sender {
    font-weight: 600;
    color: var(--accent-primary);
    font-size: 14px;
}

.chat-message .text {
    margin-top: 4px;
    word-wrap: break-word;
}

.chat-message .time {
    font-size: 11px;
    color: var(--text-secondary);
    margin-top: 4px;
}

.chat-input-container {
    display: flex;
    gap: 10px;
}

.chat-input-container input {
    flex: 1;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.chat-input-container input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.send-btn {
    width: 45px;
    height: 45px;
    border-radius: 10px;
    border: none;
    background: var(--accent-primary);
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
}

.send-btn:hover {
    background: var(--accent-secondary);
    transform: scale(1.05);
}

/* ========================================
   Modals
======================================== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--modal-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    animation: fadeIn 0.3s ease;
}

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

.modal-content {
    background: var(--bg-secondary);
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    max-width: 450px;
    width: 90%;
    animation: slideUp 0.3s ease;
    border: 1px solid var(--border-color);
}

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

.modal-content h2 {
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: 25px;
}

.modal-actions {
    display: flex;
    gap: 15px;
    justify-content: center;
}

/* ========================================
   Game Over Modal
======================================== */
.game-over-content .game-over-icon {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: linear-gradient(135deg, #ffd700, #ffb347);
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto 25px;
    font-size: 50px;
    color: white;
    animation: trophy-bounce 0.5s ease;
}

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

.game-over-icon.loss {
    background: linear-gradient(135deg, #666, #333);
}

.game-over-icon.draw {
    background: linear-gradient(135deg, #95a5a6, #7f8c8d);
}

.game-over-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

/* ========================================
   Promotion Modal
======================================== */
.promotion-content {
    padding: 30px;
}

.promotion-pieces {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.promotion-piece {
    width: 70px;
    height: 70px;
    font-size: 50px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    background: var(--bg-tertiary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.promotion-piece:hover {
    border-color: var(--accent-primary);
    transform: scale(1.1);
    background: var(--accent-primary);
}

/* ========================================
   Disconnect Modal
======================================== */
.disconnect-timer {
    font-size: 48px;
    font-weight: 700;
    color: var(--accent-primary);
    margin: 20px 0;
    font-family: 'Roboto Mono', monospace;
}

.disconnect-info {
    font-size: 14px;
    color: var(--text-secondary);
}

/* ========================================
   Toast Notifications
======================================== */
.toast-container {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 15px 25px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: 0 10px 30px var(--shadow-color);
    animation: slideInRight 0.3s ease, fadeOut 0.3s ease 2.7s forwards;
    max-width: 350px;
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(100px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

.toast.success {
    border-left: 4px solid #27ae60;
}

.toast.success i {
    color: #27ae60;
}

.toast.error {
    border-left: 4px solid #e74c3c;
}

.toast.error i {
    color: #e74c3c;
}

.toast.info {
    border-left: 4px solid #3498db;
}

.toast.info i {
    color: #3498db;
}

.toast.warning {
    border-left: 4px solid #f39c12;
}

.toast.warning i {
    color: #f39c12;
}

/* ========================================
   Scrollbar Styling
======================================== */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
    border-radius: 4px;
}

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

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

/* ========================================
   Piece Colors
======================================== */
.piece-white {
    color: #ffffff;
    text-shadow: 
        1px 1px 0 #000,
        -1px -1px 0 #000,
        1px -1px 0 #000,
        -1px 1px 0 #000;
}

.piece-black {
    color: #1a1a1a;
    text-shadow: 
        1px 1px 0 #666,
        -1px -1px 0 #666,
        1px -1px 0 #666,
        -1px 1px 0 #666;
}

/* ========================================
   Turn Indicator
======================================== */
.player-info.active-turn {
    border: 2px solid var(--accent-primary);
    box-shadow: 0 0 20px rgba(233, 69, 96, 0.3);
}

/* ========================================
   Responsive Design
======================================== */
@media (max-width: 1200px) {
    .game-screen {
        flex-direction: column;
        align-items: center;
    }
    
    .side-panel {
        width: 100%;
        max-width: 560px;
        flex-direction: row;
    }
    
    .move-history-panel,
    .chat-panel {
        flex: 1;
    }
}

@media (max-width: 768px) {
    .header {
        padding: 10px 15px;
    }
    
    .logo-text {
        font-size: 20px;
    }
    
    .lobby-title {
        font-size: 32px;
    }
    
    .lobby-options {
        grid-template-columns: 1fr;
    }
    
    .chessboard {
        width: 320px;
        height: 320px;
    }
    
    .board-square {
        width: 40px;
        height: 40px;
        font-size: 32px;
    }
    
    .board-square .coord-file,
    .board-square .coord-rank {
        font-size: 8px;
    }
    
    .check-ring {
        width: 35px;
        height: 35px;
        border-width: 3px;
    }
    
    .player-info {
        min-width: 280px;
        padding: 10px 15px;
    }
    
    .player-timer {
        font-size: 18px;
        padding: 8px 12px;
    }
    
    .side-panel {
        flex-direction: column;
    }
    
    .game-controls {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .control-btn {
        width: 45px;
        height: 45px;
    }
}

@media (max-width: 480px) {
    .chessboard {
        width: 280px;
        height: 280px;
    }
    
    .board-square {
        width: 35px;
        height: 35px;
        font-size: 28px;
    }
    
    .room-code-display span {
        font-size: 24px;
        letter-spacing: 3px;
    }
    
    .modal-content {
        padding: 25px;
    }
    
    .promotion-piece {
        width: 55px;
        height: 55px;
        font-size: 40px;
    }
}

/* ========================================
   Animation Utilities
======================================== */
.animate-fade-in {
    animation: fadeIn 0.5s ease;
}

.animate-slide-up {
    animation: slideUp 0.5s ease;
}

.animate-pulse {
    animation: pulse 2s ease infinite;
}

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

.animate-shake {
    animation: shake 0.5s ease;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

/* Move animation */
.piece-moving {
    transition: transform 0.2s ease;
    z-index: 100;
}

/* Highlight animation for last move */
.last-move-highlight {
    animation: highlight-flash 0.5s ease;
}

@keyframes highlight-flash {
    0% { background-color: var(--highlight-move); }
    50% { background-color: rgba(255, 255, 0, 0.7); }
    100% { background-color: var(--highlight-move); }
}

/* Premove styling */
.board-square.premove {
    background-color: rgba(0, 150, 255, 0.4) !important;
}

/* Board flipped state */
.chessboard.flipped {
    transform: rotate(180deg);
}

.chessboard.flipped .board-square {
    transform: rotate(180deg);
}

/* Game status indicator */
.game-status {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 20px 40px;
    border-radius: 15px;
    font-size: 24px;
    font-weight: 700;
    z-index: 100;
    animation: fadeIn 0.3s ease;
}

/* Piece shadows for 3D effect */
.board-square .piece {
    filter: drop-shadow(2px 4px 3px rgba(0, 0, 0, 0.4));
}