/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    line-height: 1.6;
}

/* 头部样式 */
header {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 28px;
    font-weight: bold;
    color: #667eea;
    text-decoration: none;
}

.logo span {
    color: #764ba2;
}

/* 导航栏样式 */
nav ul {
    display: flex;
    list-style: none;
    gap: 10px;
}

nav a {
    padding: 10px 20px;
    text-decoration: none;
    color: #333;
    border-radius: 5px;
    transition: all 0.3s ease;
    font-weight: 500;
    font-size: 14px;
}

nav a:hover, nav a.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

/* 主要内容区域 */
main {
    padding: 40px 0;
}

/* 欢迎区域 */
.welcome-section {
    background: white;
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    margin-bottom: 40px;
    text-align: center;
    position: relative;
    z-index: 1;
}

.welcome-section h1 {
    color: #667eea;
    margin-bottom: 20px;
    font-size: 36px;
}

.welcome-section p {
    color: #666;
    font-size: 18px;
    line-height: 1.8;
}

/* 子栏目区域 */
.categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 25px;
    margin-top: 60px;
    position: relative;
    z-index: 1;
}

.category-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.category-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    font-size: 20px;
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 10px;
}

.category-header .icon {
    font-size: 24px;
}

.category-content {
    padding: 20px;
}

.article-list {
    list-style: none;
}

.article-list li {
    padding: 12px 15px;
    border-bottom: 1px solid #eee;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
}

.article-list li:last-child {
    border-bottom: none;
}

.article-list li:hover {
    background: #f8f9ff;
    padding-left: 20px;
}

.article-list li::before {
    content: "▶";
    color: #667eea;
    font-size: 12px;
}

.article-list li a {
    color: #333;
    text-decoration: none;
    flex: 1;
}

.article-list li a:hover {
    color: #667eea;
}

/* 页脚样式 */
footer {
    background: rgba(255, 255, 255, 0.95);
    text-align: center;
    padding: 20px 0;
    margin-top: 40px;
    color: #666;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 15px;
    }
    
    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .categories {
        grid-template-columns: 1fr;
    }
    
    .welcome-section h1 {
        font-size: 28px;
    }
    
    .welcome-section p {
        font-size: 16px;
    }
}

/* 移除动画效果 */
.category-card {
    position: relative;
    z-index: 1;
}