* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #4a90e2;
    --secondary-color: #50c878;
    --text-color: #333;
    --text-light: #666;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

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

/* Header */
.header {
    background: var(--card-bg);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 600;
}

.nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Section */
.section-title {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-color);
    text-align: center;
}

/* Articles Grid */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.article-card {
    background: var(--card-bg);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
}

.article-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.article-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.article-content {
    padding: 1.5rem;
}

.article-category {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-bottom: 0.8rem;
}

.article-title {
    font-size: 1.3rem;
    margin-bottom: 0.8rem;
    color: var(--text-color);
    line-height: 1.4;
}

.article-excerpt {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-light);
}

/* Filter Tabs */
.filter-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.6rem 1.5rem;
    border: 2px solid var(--border-color);
    background: var(--card-bg);
    border-radius: 25px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.3s;
    color: var(--text-color);
}

.filter-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.filter-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Article Detail */
.article-detail {
    max-width: 800px;
    margin: 2rem auto;
    background: var(--card-bg);
    border-radius: 12px;
    padding: 3rem;
    box-shadow: var(--shadow);
}

.back-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    background: var(--card-bg);
    color: var(--text-color);
    text-decoration: none;
    border: 2px solid var(--border-color);
    border-radius: 25px;
    font-size: 0.95rem;
    font-weight: 500;
    margin-bottom: 2rem;
    transition: all 0.3s;
    cursor: pointer;
}

.back-button:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateX(-3px);
}

.back-button::before {
    content: '←';
    font-size: 1.2rem;
}

.article-detail-header {
    margin-bottom: 2rem;
}

.article-detail-category {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.article-detail-title {
    font-size: 2.2rem;
    margin-bottom: 1rem;
    color: var(--text-color);
    line-height: 1.3;
}

.article-detail-meta {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 2rem;
}

.article-detail-image {
    width: 100%;
    height: 400px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.article-detail-body {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-color);
}

.article-detail-body h2 {
    font-size: 1.6rem;
    margin: 2rem 0 1rem;
    color: var(--text-color);
}

.article-detail-body h3 {
    font-size: 1.3rem;
    margin: 1.5rem 0 0.8rem;
    color: var(--text-color);
}

.article-detail-body p {
    margin-bottom: 1.2rem;
}

.article-detail-body ul,
.article-detail-body ol {
    margin: 1.2rem 0;
    padding-left: 2rem;
}

.article-detail-body li {
    margin-bottom: 0.6rem;
}

.article-detail-body blockquote {
    border-left: 4px solid var(--primary-color);
    padding-left: 1.5rem;
    margin: 1.5rem 0;
    color: var(--text-light);
    font-style: italic;
}

/* About Section */
.about {
    padding: 4rem 0;
    background: var(--card-bg);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-content p {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-top: 2rem;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--text-light);
    font-size: 1rem;
}

/* Buttons */
.btn-primary {
    display: inline-block;
    padding: 0.8rem 2rem;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 25px;
    font-weight: 500;
    transition: background 0.3s;
}

.btn-primary:hover {
    background: #357abd;
}

.view-all {
    text-align: center;
    margin-top: 2rem;
}

/* Footer */
.footer {
    background: var(--text-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer .beian {
    margin-top: 0.8rem;
    font-size: 0.9rem;
    opacity: 0.8;
}

.footer .beian a {
    color: white;
    text-decoration: none;
    transition: opacity 0.3s;
}

.footer .beian a:hover {
    opacity: 1;
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

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

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

    .article-detail {
        padding: 1.5rem;
    }

    .article-detail-title {
        font-size: 1.6rem;
    }

    .stats {
        flex-direction: column;
        gap: 1.5rem;
    }

    .nav {
        gap: 1rem;
    }

    .filter-tabs {
        gap: 0.5rem;
    }

    .filter-btn {
        padding: 0.5rem 1rem;
        font-size: 0.85rem;
    }

    .back-button {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
        margin-bottom: 1.5rem;
    }
}