/* 全局样式 */
body {
    font-family: 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
    color: #333;
    line-height: 1.6;
}

/* 导航栏样式 */
.navbar {
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.4rem;
}

/* 下拉菜单样式 */
.dropdown-menu {
    z-index: 1030;
    border: none;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.dropdown-item.active {
    background-color: #0d6efd;
    color: white;
}

/* 序言页面样式 */
.preface-content {
    line-height: 1.8;
    font-size: 1.1rem;
}

.preface-content p {
    margin-bottom: 1.5rem;
    text-indent: 2em;
}

.preface-content p:first-of-type::first-letter {
    font-size: 1.5em;
    font-weight: bold;
    color: #0d6efd;
}

/* 序言摘要样式 */
.preface-excerpt {
    font-style: italic;
    color: #555;
    border-left: 4px solid #0d6efd;
    padding-left: 1.5rem;
}

.preface-excerpt p {
    line-height: 1.7;
    font-size: 1.1rem;
}

/* 主页横幅 */
.hero-section {
    background: linear-gradient(135deg, #0062cc, #0096ff);
    color: white;
    padding: 80px 0;
    margin-bottom: 30px;
}

.hero-section h1 {
    font-weight: 700;
    margin-bottom: 20px;
}

.hero-section .lead {
    font-size: 1.4rem;
    margin-bottom: 30px;
}

/* 章节卡片 */
.card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: none;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.card-title {
    color: #0062cc;
    font-weight: 600;
}

/* 章节部分 */
#chapters .card {
    margin-bottom: 20px;
}

/* 关于我们部分 */
#about {
    background-color: #f8f9fa;
}

/* 参与贡献部分 */
#contribute .border {
    transition: all 0.3s ease;
}

#contribute .border:hover {
    background-color: #f8f9fa;
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* 页脚样式 */
footer {
    margin-top: 30px;
}

footer a {
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .hero-section {
        padding: 50px 0;
    }
    
    .hero-section h1 {
        font-size: 2.5rem;
    }
    
    .hero-section .lead {
        font-size: 1.2rem;
    }
}

/* 中南大学主题色 */
.bg-primary {
    background-color: #003c8f !important; /* 中南大学蓝色 */
}

.btn-primary {
    background-color: #003c8f;
    border-color: #003c8f;
}

.btn-primary:hover {
    background-color: #002d6b;
    border-color: #002d6b;
}

.btn-outline-primary {
    color: #003c8f;
    border-color: #003c8f;
}

.btn-outline-primary:hover {
    background-color: #003c8f;
    border-color: #003c8f;
}

.card-title {
    color: #003c8f;
}

/* 自定义动画 */
.fade-in {
    animation: fadeIn 1s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}