/* Classical Chinese Aesthetic Styles */
:root {
    /* Traditional Chinese Color Palette */
    --primary-color: #8B4513; /* Saddle Brown - 棕色 */
    --secondary-color: #D2691E; /* Chocolate - 巧克力色 */
    --accent-color: #CD853F; /* Peru - 秘魯色 */
    --text-color: #2F4F4F; /* Dark Slate Gray - 深石板灰 */
    --light-text: #F5F5DC; /* Beige - 米色 */
    --background: #FFF8DC; /* Cornsilk - 玉米絲色 */
    --card-bg: #FAF0E6; /* Linen - 亞麻色 */
    --border-color: #DEB887; /* Burlywood - 桃木色 */
    --highlight: #B8860B; /* Dark Goldenrod - 深金菊色 */
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Typography */
    --font-serif: 'Noto Serif TC', serif;
    --font-sans: 'Noto Sans TC', sans-serif;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--background);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
}

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

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--light-text);
    padding: var(--spacing-xl);
    text-align: center;
    border-bottom: 3px solid var(--highlight);
}

.header-content {
    max-width: 800px;
    margin: 0 auto;
}

.title {
    font-family: var(--font-serif);
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: var(--spacing-xs);
}

.description {
    font-size: 0.9rem;
    opacity: 0.8;
    font-style: italic;
}

/* Main Content */
.main-content {
    display: flex;
    flex: 1;
    padding: var(--spacing-lg);
    gap: var(--spacing-lg);
}

/* Sidebar */
.sidebar {
    width: 300px;
    background-color: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    padding: var(--spacing-lg);
    border: 1px solid var(--border-color);
    height: fit-content;
    position: sticky;
    top: var(--spacing-lg);
}

.sidebar-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--border-color);
}

.sidebar-header h2 {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

.sidebar-header p {
    font-size: 0.8rem;
    color: var(--text-color);
    opacity: 0.7;
}

/* Sutra List */
.sutra-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.sutra-item {
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 8px 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.sutra-item:hover {
    background-color: #f5f0e6;
    border-color: var(--highlight);
}

.sutra-item.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--light-text);
    border-color: var(--highlight);
}

.sutra-title {
    font-family: var(--font-serif);
    font-size: 1rem;
    font-weight: 600;
    white-space: nowrap;
}

.sutra-subtitle {
    font-size: 0.75rem;
    opacity: 0.7;
    display: none;
}

.sutra-description {
    display: none;
}

.sutra-chapters {
    font-size: 0.7rem;
    opacity: 0.6;
    margin-left: auto;
    white-space: nowrap;
}

/* Reading Area */
.reading-area {
    flex: 1;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    padding: var(--spacing-xl);
    border: 1px solid var(--border-color);
    min-height: 600px;
}

/* Welcome Screen */
.welcome-screen {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 500px;
}

.welcome-content {
    text-align: center;
    max-width: 500px;
}

.welcome-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-lg);
}

.welcome-content h2 {
    font-family: var(--font-serif);
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.welcome-content p {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
}

.welcome-instruction {
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.7;
    font-style: italic;
}

/* Chapter Content */
.chapter-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
}

.chapter-header h2 {
    font-family: var(--font-serif);
    font-size: 2.2rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.chapter-meta {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-md);
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
}

.chapter-dropdown-wrapper select {
    font-family: var(--font-serif);
    font-size: 0.9rem;
    padding: 4px 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: white;
    color: var(--text-color);
    cursor: pointer;
}

.chapter-dropdown-wrapper select:focus {
    outline: none;
    border-color: var(--highlight);
}

.chapter-text {
    font-family: var(--font-serif);
    font-size: 1.3rem;
    line-height: 2;
    text-align: justify;
    padding: var(--spacing-lg);
    background-color: var(--card-bg);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin-bottom: var(--spacing-xl);
}

.chapter-text p {
    margin-bottom: var(--spacing-md);
    text-indent: 2em;
}

/* Chapter Navigation */
.chapter-navigation {
    display: flex;
    justify-content: space-between;
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.nav-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--light-text);
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: 6px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: var(--font-sans);
}

.nav-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

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

/* Footer */
.footer {
    background-color: var(--primary-color);
    color: var(--light-text);
    text-align: center;
    padding: var(--spacing-lg);
    font-size: 0.9rem;
}

.footer p {
    margin-bottom: var(--spacing-xs);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-content {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        position: static;
    }
    
    .sutra-list {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
        gap: 4px;
    }
    
    .sutra-item {
        padding: 6px 8px;
    }
    
    .sutra-title {
        font-size: 0.9rem;
    }
}

@media (max-width: 768px) {
    .title {
        font-size: 1.8rem;
    }
    
    .reading-area {
        padding: var(--spacing-md);
    }
    
    .chapter-text {
        font-size: 1.1rem;
        padding: var(--spacing-sm);
    }
    
    .chapter-navigation {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .nav-btn {
        width: 100%;
        padding: 8px;
    }
    
    .chapter-meta {
        flex-direction: column;
        gap: 4px;
    }
}

@media (max-width: 480px) {
    .header {
        padding: var(--spacing-md);
    }
    
    .title {
        font-size: 1.5rem;
    }
    
    .main-content {
        padding: var(--spacing-sm);
    }
    
    .sidebar {
        padding: var(--spacing-sm);
    }
    
    .reading-area {
        padding: var(--spacing-sm);
    }
    
    .chapter-text {
        font-size: 1rem;
        line-height: 1.8;
    }
    
    .sutra-list {
        grid-template-columns: 1fr;
    }
}

/* Print Styles */
@media print {
    .sidebar, .chapter-navigation, .footer {
        display: none;
    }
    
    .reading-area {
        box-shadow: none;
        border: none;
    }
    
    .chapter-text {
        font-size: 12pt;
        line-height: 1.5;
    }
}