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

:root {
    /* Light Theme Variables */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --text-primary: #333333;
    --text-secondary: #666666;
    --primary-color: #8b5cf6;
    --primary-hover: #7c3aed;
    --border-color: #e9ecef;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.1);
    --panel-bg: #ffffff;
    --overlay-bg: rgba(0, 0, 0, 0.5);
    
    /* Typography */
    --font-size-base: 16px;
    --font-family-base: Arial, sans-serif;
    --font-weight-normal: 400;
    --font-weight-bold: 600;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Dark Theme Variables */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #cccccc;
    --primary-color: #a855f7;
    --primary-hover: #9333ea;
    --border-color: #404040;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.2);
    --panel-bg: #2d2d2d;
    --overlay-bg: rgba(0, 0, 0, 0.7);
}

/* Base Typography and Layout */
body {
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Settings Panel */
.settings-panel {
    position: fixed;
    top: 0;
    right: -350px;
    width: 350px;
    height: 100vh;
    background-color: var(--panel-bg);
    box-shadow: var(--shadow);
    z-index: 1000;
    transition: right var(--transition-normal);
    overflow-y: auto;
}

.settings-panel.open {
    right: 0;
}

.settings-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--overlay-bg);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.settings-overlay.visible {
    opacity: 1;
    visibility: visible;
}

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

.settings-header h2 {
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-secondary);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: 4px;
    transition: color var(--transition-fast), background-color var(--transition-fast);
}

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

.settings-content {
    padding: var(--spacing-md);
}

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

.setting-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
}

.setting-group select {
    width: 100%;
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

.setting-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.theme-toggle {
    display: flex;
    gap: var(--spacing-xs);
}

.theme-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.theme-btn.active {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.theme-btn:hover:not(.active) {
    background-color: var(--bg-primary);
    color: var(--text-primary);
}

.font-size-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
}

.font-btn {
    width: 40px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

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

#fontSizeValue {
    min-width: 60px;
    text-align: center;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
}

/* Main Container */
.main-container {
    min-height: 100vh;
    transition: transform var(--transition-normal);
}

.main-container.shifted {
    transform: translateX(-50px);
}

/* Header */
.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    background-color: var(--bg-primary);
    border-top: 1px solid var(--border-color);
}

.settings-btn {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-primary);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: 6px;
    transition: all var(--transition-fast);
}

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

.app-header h1 {
    font-size: 1.5rem;
    font-weight: var(--font-weight-bold);
    color: var(--primary-color);
}

.header-spacer {
    width: 40px;
}

/* Content Area */
.content-area {
    padding: var(--spacing-md);
}

/* Welcome Screen */
.welcome-screen {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.welcome-content {
    animation: fadeInUp 0.6s ease-out;
}

.logo-container {
    margin-bottom: var(--spacing-lg);
}

.logo {
    width: 120px;
    height: 120px;
    margin: 0 auto;
}

#welcomeTitle {
    font-size: 2rem;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

#welcomeDescription {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

/* Bookmark Container on Home */
.bookmark-container {
    margin: var(--spacing-lg) 0;
    text-align: center;
}

.bookmark-container.hidden {
    display: none;
}

.bookmark-home-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    border: none;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 12px;
    font-size: 1rem;
    font-weight: var(--font-weight-bold);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin: 0 auto;
    box-shadow: var(--shadow);
}

.bookmark-home-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.bookmark-home-btn i {
    font-size: 1.1rem;
}

/* Chapter Grid */
.chapter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.chapter-btn {
    aspect-ratio: 1;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: clamp(2rem, 5vw, 3.5rem) !important;
    font-weight: var(--font-weight-bold);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 60px;
}

.chapter-btn:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

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

/* Chapter View */
.chapter-view {
    max-width: 800px;
    margin: 0 auto;
    height: calc(100vh - 80px); /* Account for header height */
    display: flex;
    flex-direction: column;
}

.chapter-view.hidden {
    display: none;
}

.chapter-header {
    display: flex;
    flex-direction: row !important;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-xs);
    padding-bottom: var(--spacing-xs);
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0; /* Prevent header from shrinking */
}

.nav-btn {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-xs) var(--spacing-sm);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 40px;
    height: 40px;
}

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

.nav-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.nav-btn:disabled:hover {
    background-color: transparent;
    color: var(--text-primary);
    border-color: var(--border-color);
}

#chapterTitle {
    font-size: 1.5rem;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
}

.chapter-actions {
    display: flex;
    flex-direction: row !important;
    align-items: center;
    gap: var(--spacing-sm);
}

.chapter-nav {
    display: flex;
    gap: var(--spacing-xs);
}

.bookmark-btn {
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

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

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

/* Audio Controls */
.audio-controls {
    background-color: var(--bg-secondary);
    border-radius: 12px;
    padding: var(--spacing-xs);
    margin-bottom: var(--spacing-xs);
    flex-shrink: 0; /* Prevent audio controls from shrinking */
}

.audio-player {
    display: flex;
    flex-direction: row !important;
    align-items: center;
    gap: var(--spacing-md);
}

.audio-btn {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 48px;
    height: 48px;
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

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

.progress-container {
    flex: 1;
}

.progress-bar {
    height: 6px;
    background-color: var(--border-color);
    border-radius: 3px;
    overflow: hidden;
    cursor: pointer;
    margin-bottom: var(--spacing-xs);
}

.progress-fill {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.1s ease;
}

.time-display {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Chapter Content */
.chapter-content {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.chapter-text {
    background-color: var(--bg-secondary);
    border-radius: 12px;
    padding: var(--spacing-xs);
    line-height: 1.8;
    overflow-y: auto;
    flex: 1;
    min-height: 200px;
    max-height: fit-content !important;
}

#chapterContent {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin: 0;
}

/* Chapter content HTML styling */
#chapterContent h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: var(--spacing-sm);
    font-weight: var(--font-weight-bold);
}

#chapterContent p {
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

#chapterContent strong {
    color: var(--primary-color);
    font-weight: var(--font-weight-bold);
}

#chapterContent em {
    font-style: italic;
    color: var(--text-secondary);
}

#chapterContent ul, #chapterContent ol {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-lg);
}

#chapterContent li {
    margin-bottom: var(--spacing-xs);
    line-height: 1.6;
}

#chapterContent blockquote {
    border-left: 4px solid var(--primary-color);
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--bg-primary);
    border-radius: 0 8px 8px 0;
    font-style: italic;
}

#chapterContent blockquote em {
    color: var(--text-primary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .settings-panel {
        width: 100vw;
        right: -100vw;
    }
    
    .chapter-grid {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
        gap: var(--spacing-sm);
    }
    
    .chapter-btn {
        min-height: 50px;
        font-size: 0.9rem;
    }
    
    .audio-player {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .progress-container {
        width: 100%;
    }
    
    .chapter-view {
        height: calc(100vh - 60px); /* Smaller header on mobile */
    }
    
    .chapter-header {
        flex-direction: column;
        gap: var(--spacing-sm);
        text-align: center;
    }
    
    .chapter-actions {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .chapter-nav {
        justify-content: center;
    }
    
    #welcomeTitle {
        font-size: 1.5rem;
    }
    
    #welcomeDescription {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .content-area {
        padding: var(--spacing-sm);
    }
    
    .app-header {
        padding: var(--spacing-sm);
    }
    
    .chapter-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--spacing-xs);
    }
    
    .settings-content {
        padding: var(--spacing-sm);
    }
    
    .audio-controls,
    .chapter-text {
        padding: var(--spacing-sm);
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.chapter-view {
    animation: slideInRight 0.4s ease-out;
}

/* Focus styles for accessibility */
button:focus,
select:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Loading states */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

/* Error states */
.error {
    color: #dc3545;
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
    padding: var(--spacing-sm);
    border-radius: 6px;
    margin: var(--spacing-sm) 0;
}