:root {
    --bg-primary: #f5f5f0;
    --bg-secondary: #ffffff;
    --bg-card: #ffffff;
    --bg-card-hover: #fafafa;

    --text-primary: #1a1a1a;
    --text-secondary: #4a4a4a;
    --text-muted: #7a7a7a;

    --border-color: #e0e0e0;
    --border-hover: #c0c0c0;

    --color-robot: #3b82f6;
    --color-create: #10b981;
    --color-join: #f59e0b;
    --color-deck: #8b5cf6;
    --color-help: #ec4899;

    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #3b82f6;

    --font-display: 'Cinzel', serif;
    --font-body: 'Inter', sans-serif;

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    --radius-sm: 2px;
    --radius-md: 4px;
    --radius-lg: 6px;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);

    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
}

.app-container {
    position: relative;
    min-height: 100vh;
}

.section {
    display: none;
    position: relative;
    min-height: 100vh;
}

.section.active {
    display: block;
}

.auth-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: var(--spacing-xl);
}

.logo-container {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.game-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 8vw, 3.5rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.title-glow {
    display: block;
}

.title-sub {
    display: block;
    font-size: 0.4em;
    letter-spacing: 0.5em;
    color: var(--text-secondary);
    margin-top: var(--spacing-sm);
}

.tagline {
    font-size: 1rem;
    color: var(--text-muted);
    letter-spacing: 0.1em;
}

.auth-form {
    display: none;
    width: 100%;
    max-width: 400px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-md);
}

.auth-form.active {
    display: block;
}

.auth-form h2 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    color: var(--text-primary);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.form-group input {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all var(--transition-normal);
}

.form-group input:focus {
    outline: none;
    border-color: var(--text-primary);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

.auth-switch {
    text-align: center;
    margin-top: var(--spacing-lg);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.auth-switch a {
    color: var(--text-primary);
    text-decoration: underline;
    font-weight: 600;
    transition: opacity var(--transition-fast);
}

.auth-switch a:hover {
    opacity: 0.7;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
    text-decoration: none;
}

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

.btn-primary:hover {
    opacity: 0.85;
    transform: translateY(-1px);
}

.btn-primary:active {
    transform: translateY(0);
}

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

.btn-secondary:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-hover);
}

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    padding: var(--spacing-sm) var(--spacing-md);
}

.btn-ghost:hover {
    color: var(--text-primary);
    background: rgba(0, 0, 0, 0.05);
}

.btn-small {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
}

.btn-full {
    width: 100%;
}

.btn-icon {
    width: 20px;
    height: 20px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.lobby-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg) var(--spacing-xl);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.lobby-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    color: var(--text-primary);
}

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

#user-display-name {
    font-weight: 600;
}

.user-stats {
    display: flex;
    gap: var(--spacing-md);
}

.stat {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    font-weight: 500;
}

.stat.win {
    color: var(--success);
}

.stat.loss {
    color: var(--danger);
}

.lobby-content {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 70px);
    padding: var(--spacing-xl);
}

.lobby-menu {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    width: 100%;
    max-width: 900px;
}

.menu-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-xl);
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    text-align: left;
    position: relative;
    overflow: hidden;
}

.menu-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    transition: width var(--transition-normal);
}

.menu-btn:hover::before {
    width: 100%;
    opacity: 0.1;
}

.menu-btn:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.menu-btn[data-color="robot"]::before {
    background: var(--color-robot);
}

.menu-btn[data-color="robot"]:hover {
    border-color: var(--color-robot);
}

.menu-btn[data-color="robot"] .menu-btn-icon {
    color: var(--color-robot);
}

.menu-btn[data-color="create"]::before {
    background: var(--color-create);
}

.menu-btn[data-color="create"]:hover {
    border-color: var(--color-create);
}

.menu-btn[data-color="create"] .menu-btn-icon {
    color: var(--color-create);
}

.menu-btn[data-color="join"]::before {
    background: var(--color-join);
}

.menu-btn[data-color="join"]:hover {
    border-color: var(--color-join);
}

.menu-btn[data-color="join"] .menu-btn-icon {
    color: var(--color-join);
}

.menu-btn[data-color="deck"]::before {
    background: var(--color-deck);
}

.menu-btn[data-color="deck"]:hover {
    border-color: var(--color-deck);
}

.menu-btn[data-color="deck"] .menu-btn-icon {
    color: var(--color-deck);
}

.menu-btn[data-color="help"]::before {
    background: var(--color-help);
}

.menu-btn[data-color="help"]:hover {
    border-color: var(--color-help);
}

.menu-btn[data-color="help"] .menu-btn-icon {
    color: var(--color-help);
}

.menu-btn-icon {
    font-size: 1.5rem;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    position: relative;
    z-index: 1;
}

.menu-btn-icon svg {
    width: 24px;
    height: 24px;
}

.menu-btn-text {
    flex: 1;
    position: relative;
    z-index: 1;
}

.menu-btn-title {
    display: block;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.menu-btn-desc {
    display: block;
    font-size: 0.85rem;
    color: var(--text-muted);
}

#notification-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.notification {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--info);
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease;
    max-width: 350px;
}

.notification.success {
    border-left-color: var(--success);
}

.notification.error {
    border-left-color: var(--danger);
}

.notification.warning {
    border-left-color: var(--warning);
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(100px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 900;
}

.modal-overlay.active {
    display: flex;
}

.modal-content {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-2xl);
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(245, 245, 240, 0.9);
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1100;
}

.loading-overlay.active {
    display: flex;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--text-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-text {
    margin-top: var(--spacing-lg);
    color: var(--text-secondary);
}

@media (max-width: 768px) {
    .lobby-header {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }

    .user-info {
        flex-wrap: wrap;
        justify-content: center;
    }

    .lobby-menu {
        grid-template-columns: 1fr;
    }

    .menu-btn {
        padding: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .auth-container {
        padding: var(--spacing-md);
    }

    .auth-form {
        padding: var(--spacing-lg);
    }

    .game-title {
        font-size: 1.75rem;
    }
}

.deck-builder {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.deck-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.deck-header h1 {
    font-family: var(--font-display);
    font-size: 1.25rem;
}

.deck-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.deck-info-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
}

.deck-name-container input {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    min-width: 200px;
}

.deck-stats {
    display: flex;
    gap: var(--spacing-xl);
}

.deck-stat {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.deck-stat strong {
    color: var(--text-primary);
}

.deck-builder-content {
    display: grid;
    grid-template-columns: 1fr 320px;
    flex: 1;
    overflow: hidden;
}

.card-pool {
    padding: var(--spacing-lg);
    overflow-y: auto;
    max-height: calc(100vh - 140px);
}

.card-pool-tabs {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.tab-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.tab-btn.active {
    background: var(--text-primary);
    color: var(--bg-secondary);
    border-color: var(--text-primary);
}

.card-pool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: var(--spacing-md);
}

.pool-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    overflow: hidden;
}

.pool-card:hover {
    border-color: var(--text-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.pool-card.at-limit {
    opacity: 0.5;
}

.pool-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    font-weight: 600;
    font-size: 0.85rem;
}

.pool-card-header.monster {
    background: #2563eb;
    color: white;
}

.pool-card-header.magic {
    background: #9333ea;
    color: white;
}

.card-count {
    font-size: 0.75rem;
    opacity: 0.8;
}

.pool-card-body {
    padding: var(--spacing-md);
    min-height: 60px;
}

.card-stats {
    display: flex;
    gap: var(--spacing-md);
}

.stat-attack {
    color: #dc2626;
    font-weight: 700;
}

.stat-attack::before {
    content: 'A:';
    font-weight: 400;
    opacity: 0.7;
}

.stat-defense {
    color: #2563eb;
    font-weight: 700;
}

.stat-defense::before {
    content: 'D:';
    font-weight: 400;
    opacity: 0.7;
}

.summon-time {
    display: inline-block;
    margin-top: var(--spacing-sm);
    font-size: 0.75rem;
    color: var(--text-muted);
    background: var(--bg-primary);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
}

.card-effect {
    font-size: 0.75rem;
    color: var(--text-secondary);
    line-height: 1.4;
}

.pool-card-footer {
    padding: var(--spacing-sm) var(--spacing-md);
    border-top: 1px solid var(--border-color);
    background: var(--bg-primary);
}

.card-value {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.deck-preview {
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    padding: var(--spacing-lg);
    overflow-y: auto;
    max-height: calc(100vh - 140px);
}

.deck-preview h3 {
    font-size: 1rem;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--border-color);
}

.deck-cards-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.empty-deck-message {
    color: var(--text-muted);
    font-size: 0.9rem;
    text-align: center;
    padding: var(--spacing-xl);
}

.deck-card-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--border-color);
}

.deck-card-item.monster {
    border-left-color: #2563eb;
}

.deck-card-item.magic {
    border-left-color: #9333ea;
}

.deck-card-name {
    font-size: 0.85rem;
    font-weight: 500;
}

.deck-card-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.qty-btn {
    width: 24px;
    height: 24px;
    border: 1px solid var(--border-color);
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

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

.qty {
    min-width: 20px;
    text-align: center;
    font-weight: 600;
}

.deck-list-container {
    max-height: 300px;
    overflow-y: auto;
}

.deck-list-item {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.deck-list-name {
    font-weight: 600;
}

.deck-list-info {
    color: var(--text-muted);
    font-size: 0.85rem;
}

@media (max-width: 900px) {
    .deck-builder-content {
        grid-template-columns: 1fr;
    }

    .deck-preview {
        border-left: none;
        border-top: 1px solid var(--border-color);
        max-height: 300px;
    }

    .card-pool {
        max-height: 400px;
    }
}