:root {
    /* Color Palette - Traditional Chinese Chess Colors */
    --red-primary: #C41E3A;
    --red-light: #E63946;
    --red-dark: #8B0000;
    --black-primary: #1A1A1A;
    --black-light: #2D2D2D;
    --wood-light: #D4A574;
    --wood-dark: #8B6F47;
    --gold: #FFD700;
    --gold-dark: #B8860B;
    
    /* UI Colors */
    --bg-gradient-start: #0f0c29;
    --bg-gradient-mid: #302b63;
    --bg-gradient-end: #24243e;
    --surface: rgba(255, 255, 255, 0.05);
    --surface-hover: rgba(255, 255, 255, 0.1);
    --text-primary: #FFFFFF;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --border: rgba(255, 255, 255, 0.2);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(255, 215, 0, 0.3);
}

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

body {
    font-family: 'Noto Sans SC', sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-mid), var(--bg-gradient-end));
    min-height: 100vh;
    color: var(--text-primary);
    overflow-x: hidden;
}

.app-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-md);
}

/* Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md);
    background: var(--surface);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
}

.title {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.title-chinese {
    font-family: 'Ma Shan Zheng', cursive;
    font-size: 2.5rem;
    background: linear-gradient(135deg, var(--gold), var(--red-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 0 30px rgba(255, 215, 0, 0.5);
}

.title-english {
    font-size: 0.875rem;
    color: var(--text-secondary);
    letter-spacing: 2px;
    text-transform: uppercase;
}

.menu-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: var(--spacing-sm);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 4px;
    transition: all 0.3s ease;
}

.menu-btn span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.menu-btn:hover {
    background: var(--surface-hover);
    transform: scale(1.05);
}

/* Main Menu */
.main-menu {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
}

.menu-content {
    text-align: center;
    width: 100%;
    max-width: 800px;
}

.menu-content h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-xl);
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.menu-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.menu-button {
    background: var(--surface);
    backdrop-filter: blur(10px);
    border: 2px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    text-align: left;
}

.menu-button:hover {
    background: var(--surface-hover);
    border-color: var(--gold);
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.button-icon {
    font-size: 3rem;
    flex-shrink: 0;
}

.button-text {
    flex: 1;
}

.button-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.button-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(5px);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.modal.active {
    display: flex;
}

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

.modal-content {
    background: linear-gradient(135deg, var(--bg-gradient-mid), var(--bg-gradient-end));
    border: 2px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    max-width: 600px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s ease;
}

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

.modal-content h2 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    font-size: 1.75rem;
}

/* Difficulty Selection */
.difficulty-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.difficulty-btn {
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.difficulty-btn:hover {
    background: var(--surface-hover);
    border-color: var(--gold);
    transform: scale(1.05);
}

.difficulty-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-xs);
}

.difficulty-name {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.difficulty-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Online Options */
.online-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.online-btn {
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
}

.online-btn:hover {
    background: var(--surface-hover);
    border-color: var(--gold);
    transform: scale(1.05);
}

.online-btn .button-icon {
    font-size: 2.5rem;
}

.online-btn .button-text {
    font-size: 1.125rem;
    font-weight: 600;
}

/* Room Input */
.room-input-container {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

#roomCodeInput {
    flex: 1;
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    color: var(--text-primary);
    font-size: 1.125rem;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 4px;
}

#roomCodeInput:focus {
    outline: none;
    border-color: var(--gold);
}

/* Room Code Display */
.room-code-display {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.room-code-display p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

.room-code {
    background: var(--surface);
    border: 2px solid var(--gold);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: 8px;
    color: var(--gold);
    margin-bottom: var(--spacing-md);
    text-shadow: var(--shadow-glow);
}

.waiting-text {
    font-style: italic;
    animation: pulse 2s ease-in-out infinite;
}

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

/* Buttons */
.confirm-btn, .cancel-btn {
    width: 100%;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.confirm-btn {
    background: linear-gradient(135deg, var(--gold-dark), var(--gold));
    color: var(--black-primary);
    margin-bottom: var(--spacing-sm);
}

.confirm-btn:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-glow);
}

.cancel-btn {
    background: var(--surface);
    color: var(--text-primary);
    border-color: var(--border);
}

.cancel-btn:hover {
    background: var(--surface-hover);
}

/* Game Container */
.game-container {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: var(--spacing-lg);
    align-items: start;
}

/* Game Info */
.game-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    grid-column: 1 / -1;
    background: var(--surface);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    border: 1px solid var(--border);
}

.player-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.player-avatar {
    font-size: 2.5rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--surface);
    border-radius: 50%;
    border: 2px solid var(--border);
}

.red-player .player-avatar {
    border-color: var(--red-primary);
    box-shadow: 0 0 20px rgba(196, 30, 58, 0.3);
}

.black-player .player-avatar {
    border-color: var(--black-light);
}

.player-name {
    font-size: 1.25rem;
    font-weight: 700;
}

.player-status {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

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

.turn-indicator {
    font-size: 1.125rem;
    font-weight: 600;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--surface);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
}

.back-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: var(--spacing-xs) var(--spacing-md);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.back-btn:hover {
    background: var(--surface-hover);
    transform: scale(1.05);
}

/* Board Wrapper */
.board-wrapper {
    position: relative;
    grid-column: 2;
}

#chessBoard {
    display: block;
    background: linear-gradient(135deg, var(--wood-light), var(--wood-dark));
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 3px solid var(--gold-dark);
    cursor: pointer;
}

/* Emoji Container */
.emoji-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 10;
}

.floating-emoji {
    position: absolute;
    font-size: 3rem;
    animation: floatUp 2s ease-out forwards;
    pointer-events: none;
}

@keyframes floatUp {
    0% {
        transform: translateY(0) scale(0);
        opacity: 0;
    }
    20% {
        opacity: 1;
        transform: scale(1);
    }
    100% {
        transform: translateY(-200px) scale(0.5);
        opacity: 0;
    }
}

/* Emoji Picker */
.emoji-picker {
    grid-column: 1;
    background: var(--surface);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    border: 1px solid var(--border);
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
}

.emoji-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: var(--spacing-sm);
    font-size: 2rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.emoji-btn:hover {
    background: var(--surface-hover);
    transform: scale(1.1);
}

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

/* Move History */
.move-history {
    grid-column: 3;
    background: var(--surface);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    border: 1px solid var(--border);
    max-height: 600px;
    overflow-y: auto;
}

.move-history h3 {
    margin-bottom: var(--spacing-md);
    text-align: center;
    color: var(--gold);
}

.moves-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.move-item {
    background: var(--surface);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-family: monospace;
    font-size: 0.875rem;
}

/* Game Over Buttons */
.game-over-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .game-container {
        grid-template-columns: 1fr;
    }
    
    .board-wrapper {
        grid-column: 1;
        justify-self: center;
    }
    
    .emoji-picker {
        grid-column: 1;
        grid-template-columns: repeat(5, 1fr);
    }
    
    .move-history {
        grid-column: 1;
    }
}

@media (max-width: 768px) {
    .title-chinese {
        font-size: 2rem;
    }
    
    .menu-buttons {
        grid-template-columns: 1fr;
    }
    
    .difficulty-buttons {
        grid-template-columns: 1fr;
    }
    
    .online-options {
        grid-template-columns: 1fr;
    }
    
    #chessBoard {
        width: 100%;
        height: auto;
    }
    
    .emoji-picker {
        grid-template-columns: repeat(5, 1fr);
    }
}

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

::-webkit-scrollbar-track {
    background: var(--surface);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb {
    background: var(--gold-dark);
    border-radius: var(--radius-sm);
}

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