/* ===== 基础重置 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: #4b5563;
    line-height: 1.6;
    background: #ffffff;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== 导航栏 ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid #e5e7eb;
    z-index: 100;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.logo {
    font-size: 1.3rem;
    font-weight: 700;
    color: #111827;
    text-decoration: none;
    letter-spacing: -0.5px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-menu a {
    text-decoration: none;
    color: #4b5563;
    font-size: 0.9rem;
    transition: color 0.2s;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: #2563eb;
}

/* ===== Hero 区域 ===== */
.hero {
    padding: 120px 0 60px;
    text-align: center;
    background: transparent;
}

.hero-content h1 {
    font-size: 2.3rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 12px;
    letter-spacing: -0.8px;
}

.hero-content p {
    font-size: 1rem;
    color: #5b6b7a;
    max-width: 520px;
    margin: 0 auto 28px;
}

.search-box {
    display: flex;
    max-width: 480px;
    margin: 0 auto;
    gap: 0;
}

.search-box input {
    flex: 1;
    padding: 14px 20px;
    border: 1px solid #ddd;
    border-right: none;
    border-radius: 8px 0 0 8px;
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.2s;
}

.search-box input:focus {
    border-color: #2c3e50;
}

.search-box button {
    padding: 14px 28px;
    background: #2c3e50;
    color: #fff;
    border: none;
    border-radius: 0 8px 8px 0;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.2s;
}

.search-box button:hover {
    background: #1a252f;
}

/* ===== 通用区块 ===== */
.section {
    padding: 64px 0;
}

.section-title {
    font-size: 1.6rem;
    font-weight: 600;
    color: #2c3e50;
    text-align: center;
    margin-bottom: 48px;
    letter-spacing: -0.5px;
}

.bg-light {
    background: #f8f9fa;
}

/* ===== 分类卡片 ===== */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}

.category-card {
    background: #fff;
    border: 1px solid #e5e7eb;
    border-radius: 12px;
    padding: 24px 18px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
}

.category-card:hover {
    border-color: #94a3b8;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(15, 23, 42, 0.08);
}

.category-icon {
    font-size: 1.8rem;
    margin-bottom: 10px;
}

.category-card h3 {
    font-size: 1rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 6px;
}

.category-card p {
    font-size: 0.88rem;
    color: #6b7280;
}

/* ===== 文章卡片 ===== */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.article-card {
    background: #fff;
    border: 1px solid #eee;
    border-radius: 12px;
    padding: 28px;
    transition: all 0.3s ease;
}

.article-card:hover {
    border-color: #2c3e50;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.article-tag {
    display: inline-block;
    padding: 4px 12px;
    background: #f0f0f0;
    border-radius: 4px;
    font-size: 0.75rem;
    color: #666;
    margin-bottom: 12px;
}

.article-card h3 {
    font-size: 1.05rem;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 10px;
    line-height: 1.5;
}

.article-card p {
    font-size: 0.88rem;
    color: #888;
    margin-bottom: 16px;
    line-height: 1.6;
}

.article-meta {
    font-size: 0.8rem;
    color: #aaa;
}

/* ===== 简洁文章列表 ===== */
.articles-list-container {
    max-width: 820px;
    margin: 0 auto;
}
.articles-list {
    list-style: none;
    padding: 0;
    margin: 0;
}
.article-item {
    display: flex;
    gap: 14px;
    padding: 16px 0;
    border-bottom: 1px solid #eef2f6;
    align-items: center;
}
.item-left .article-tag {
    display: inline-block;
    padding: 6px 10px;
    background: #f1f5f9;
    border-radius: 6px;
    color: #374151;
    font-size: 0.82rem;
}
.item-main h3 {
    margin: 0;
    font-size: 1.05rem;
    color: #0f172a;
}
.article-meta {
    font-size: 0.82rem;
    color: #6b7280;
    margin-top: 6px;
}
.no-results {
    text-align: center;
    color: #6b7280;
    padding: 24px 0;
}

/* ===== 关于 ===== */
.about-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.about-content p {
    font-size: 1rem;
    color: #666;
    line-height: 1.8;
    margin-bottom: 48px;
}

.about-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 4px;
}

.stat-label {
    font-size: 0.85rem;
    color: #999;
}

/* ===== 页脚 ===== */
.footer {
    padding: 24px 0 36px;
    border-top: 1px solid #edf2f7;
    text-align: center;
}

.footer p {
    font-size: 0.85rem;
    color: #aaa;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .hero-content h1 {
        font-size: 2rem;
    }

    .categories-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .articles-grid {
        grid-template-columns: 1fr;
    }

    .about-stats {
        flex-direction: column;
        gap: 32px;
    }

    .nav-menu {
        gap: 20px;
    }
}

@media (max-width: 480px) {
    .categories-grid {
        grid-template-columns: 1fr;
    }

    .hero {
        padding: 120px 0 60px;
    }

    .hero-content h1 {
        font-size: 1.6rem;
    }
}