:root {
    --primary-color: #ffb546;
}

body {
    font-family: 'Microsoft YaHei', sans-serif;
    transition: background-color 0.3s ease, color 0.3s ease;
}

body.light-theme {
    background-color: #f8f9fa;
    color: #333;
}

.light-theme .chapter-content {
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 0 5px rgba(0,0,0,0.05);
}

.light-theme .chapter-header {
    border-bottom: 1px solid #eee;
}

.light-theme .chapter-meta {
    color: #666;
}

.light-theme .reading-settings {
    background-color: #f1f1f1;
}

.light-theme .chapter-nav {
    border-top: 1px solid #eee;
    border-bottom: 1px solid #eee;
}

body.sepia-theme {
    background-color: #f4ecd8;
    color: #5b4636;
}

.sepia-theme .chapter-content {
    background-color: #f9f1e0;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 0 5px rgba(0,0,0,0.05);
}

.sepia-theme .chapter-header {
    border-bottom: 1px solid #e0d5b8;
}

.sepia-theme .chapter-meta {
    color: #8a7b69;
}

.sepia-theme .reading-settings {
    background-color: #f0e6d0;
}

.sepia-theme .chapter-nav {
    border-top: 1px solid #e0d5b8;
    border-bottom: 1px solid #e0d5b8;
}

body.dark-theme {
    background-color: #222;
    color: #ddd;
}

.dark-theme .chapter-content {
    background-color: #333;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 0 5px rgba(0,0,0,0.2);
}

.dark-theme .chapter-header {
    border-bottom: 1px solid #444;
}

.dark-theme .chapter-meta {
    color: #aaa;
}

.dark-theme .reading-settings {
    background-color: #383838;
}

.dark-theme .chapter-nav {
    border-top: 1px solid #444;
    border-bottom: 1px solid #444;
}

.chapter-header {
    padding-bottom: 15px;
    margin-bottom: 20px;
}

.chapter-title {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 5px;
}

.chapter-meta {
    font-size: 0.9rem;
}

.chapter-content {
    line-height: 2;
    text-align: justify;
    margin-bottom: 30px;
    transition: font-size 0.3s ease;
}

.font-size-small {
    font-size: 1rem !important;
}

.font-size-medium {
    font-size: 1.1rem !important;
}

.font-size-large {
    font-size: 1.2rem !important;
}

.chapter-nav {
    margin: 30px 0;
    padding: 15px 0;
}

.reading-settings {
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
}

.setting-title {
    font-weight: bold;
    margin-bottom: 10px;
}

.setting-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.font-size-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.theme-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
}

.theme-light {
    background-color: #fff;
    border: 1px solid #ddd;
}

.theme-sepia {
    background-color: #f4ecd8;
    border: 1px solid #e0d5b8;
}

.theme-dark {
    background-color: #333;
    border: 1px solid #222;
}

.book-mark {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 1000;
}

.book-mark .btn {
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    margin-bottom: 10px;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

@media (max-width: 767.98px) {
    .book-mark {
        display: none;
    }

    .chapter-content {
        font-size: 1rem;
        line-height: 1.8;
    }
}