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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

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

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

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: #667eea;
    text-decoration: none;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

/* 下拉菜单 */
.dropdown {
    position: relative;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: white;
    min-width: 250px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    border-radius: 12px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    list-style: none;
    padding: 0.5rem 0;
    z-index: 1001;
}

.dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu li {
    padding: 0;
}

.dropdown-menu a {
    display: block;
    padding: 0.75rem 1.5rem;
    color: #333;
    text-decoration: none;
    transition: all 0.3s ease;
    border-radius: 0;
}

.dropdown-menu a:hover {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    transform: none;
    box-shadow: none;
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #667eea;
}

/* 主内容区 */
.main {
    padding: 2rem 0;
}

.hero {
    text-align: center;
    padding: 3rem 0;
    color: white;
    margin-bottom: 3rem;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
}

/* 分类卡片 */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.category-card {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.category-card h3 {
    color: #667eea;
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.category-card p {
    color: #666;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

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

.article-list li {
    margin-bottom: 0.75rem;
}

.article-list a {
    color: #333;
    text-decoration: none;
    padding: 0.5rem 0;
    display: block;
    border-left: 3px solid transparent;
    padding-left: 1rem;
    transition: all 0.3s ease;
    border-radius: 4px;
}

.article-list a:hover {
    border-left-color: #667eea;
    background: rgba(102, 126, 234, 0.05);
    color: #667eea;
    transform: translateX(5px);
}

/* 底部 */
.footer {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
    color: #666;
}

/* 文章页面样式 */
.article-header {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.article-nav {
    background: white;
    border-radius: 12px;
    padding: 1rem;
    margin-bottom: 2rem;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.article-nav a {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
}

.article-nav a:hover {
    text-decoration: underline;
}

.article-content {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    line-height: 1.8;
}

.article-content img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 1rem 0;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-list {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
        border-radius: 0 0 12px 12px;
    }

    .nav-list.active {
        display: flex;
    }

    .mobile-menu-btn {
        display: block;
    }

    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: #f8f9fa;
        margin-top: 0.5rem;
        border-radius: 8px;
    }

    .hero h2 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .category-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .category-card {
        padding: 1.5rem;
    }

    .container {
        padding: 0 15px;
    }
}

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

.category-card {
    animation: fadeInUp 0.6s ease forwards;
}

.category-card:nth-child(1) { animation-delay: 0.1s; }
.category-card:nth-child(2) { animation-delay: 0.2s; }
.category-card:nth-child(3) { animation-delay: 0.3s; }
.category-card:nth-child(4) { animation-delay: 0.4s; }
.category-card:nth-child(5) { animation-delay: 0.5s; }

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, #5a6fd8, #6a4190);
}