:root {
    --primary-color: #2c3e50;
    --accent-color: #3498db;
    --bg-color: #f4f7f6;
    --text-color: #333;
    --active-bg: #e8f4fd;
    --border-color: #ddd;
    --progress-bg: #ecf0f1;
    --btn-color: #27ae60;
    --btn-hover: #2ecc71;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

header h1 {
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 30px;
}

.player-section {
    position: sticky;
    top: 0;
    background: white;
    padding: 20px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 30px;
    z-index: 1000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

audio {
    width: 100%;
    margin-bottom: 15px;
}

#current-chapter-display h2 {
    margin: 5px 0;
    font-size: 1.2rem;
    color: var(--primary-color);
}

.progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 5px;
}

.chapter-progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--progress-bg);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 5px;
    cursor: pointer;
}

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

.timestamp-display {
    color: #7f8c8d;
    font-size: 0.9rem;
    margin: 0;
    text-align: right;
    font-family: monospace;
}

.share-btn {
    background: none;
    border: none;
    color: var(--accent-color);
    cursor: pointer;
    font-size: 0.8rem;
    padding: 0;
    text-decoration: underline;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.share-btn:hover {
    opacity: 1;
}

.chapters-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.chapter-card {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 15px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.chapter-card:hover {
    border-color: var(--accent-color);
    background-color: #fafafa;
}

.chapter-card.active {
    background-color: var(--active-bg);
    border-color: var(--accent-color);
    border-left: 5px solid var(--accent-color);
}

.chapter-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 8px;
}

.chapter-title {
    font-weight: bold;
    font-size: 1.1rem;
    color: var(--primary-color);
}

.chapter-time {
    font-family: monospace;
    color: #7f8c8d;
    background: #eee;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.85rem;
}

.chapter-desc {
    color: #555;
    font-size: 0.95rem;
    margin: 0;
}