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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

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

/* 导航栏 */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo h2 {
    color: white;
    font-size: 1.5rem;
}

.nav-logo i {
    margin-right: 10px;
    color: #ffd700;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: #ffd700;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: white;
    margin: 3px 0;
    transition: 0.3s;
}

/* 主要内容 */
main {
    margin-top: 70px;
}

/* 英雄区域 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 100px 0;
    text-align: center;
}

.hero-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    font-weight: 700;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 40px;
    opacity: 0.9;
}

.search-container {
    display: flex;
    max-width: 500px;
    margin: 0 auto;
    background: white;
    border-radius: 50px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

#searchInput {
    flex: 1;
    padding: 15px 25px;
    border: none;
    outline: none;
    font-size: 1rem;
    color: #333;
}

#searchBtn {
    background: #ffd700;
    border: none;
    padding: 15px 25px;
    cursor: pointer;
    color: #333;
    font-size: 1rem;
    transition: background 0.3s ease;
}

#searchBtn:hover {
    background: #ffed4e;
}

/* 精选文章区域 */
.featured-section {
    padding: 80px 0;
    background: white;
}

.featured-section h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #333;
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.featured-card {
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
}

.featured-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}

.card-image {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 40px;
    text-align: center;
}

.card-image i {
    font-size: 3rem;
    color: white;
}

.card-content {
    padding: 30px;
}

.card-content h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: #333;
}

.card-content p {
    color: #666;
    margin-bottom: 20px;
    line-height: 1.6;
}

.card-meta {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.tag {
    background: #e3f2fd;
    color: #1976d2;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.date {
    color: #999;
    font-size: 0.9rem;
    margin-left: auto;
}

/* 文章区域 */
.articles-section {
    padding: 80px 0;
    background: #f8f9fa;
}

.articles-section h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #333;
}

.filter-tabs {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 50px;
    flex-wrap: wrap;
}

.filter-btn {
    background: white;
    border: 2px solid #ddd;
    padding: 10px 20px;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.filter-btn.active,
.filter-btn:hover {
    background: #667eea;
    color: white;
    border-color: #667eea;
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

/* 工具区域 */
.tools-section {
    padding: 80px 0;
    background: white;
}

.tools-section h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #333;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
}

.tool-card {
    background: white;
    padding: 40px 20px;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
    border: 2px solid transparent;
}

.tool-card:hover {
    transform: translateY(-5px);
    border-color: #667eea;
}

.tool-card i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 20px;
}

.tool-card h3 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: #333;
}

.tool-card p {
    color: #666;
    font-size: 0.9rem;
}

/* 页脚 */
.footer {
    background: #2c3e50;
    color: white;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h3 {
    margin-bottom: 20px;
    color: #ffd700;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 10px;
}

.footer-section ul li a {
    color: #bdc3c7;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section ul li a:hover {
    color: #ffd700;
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    color: #bdc3c7;
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: #ffd700;
}

.footer-bottom {
    border-top: 1px solid #34495e;
    padding-top: 20px;
    text-align: center;
    color: #bdc3c7;
}

/* 响应式设计 */
@media screen and (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: rgba(102, 126, 234, 0.95);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0,0,0,0.05);
        padding: 20px 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .hero h1 {
        font-size: 2rem;
    }

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

    .search-container {
        flex-direction: column;
        border-radius: 10px;
    }

    #searchInput,
    #searchBtn {
        border-radius: 0;
    }

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

    .filter-tabs {
        justify-content: flex-start;
        overflow-x: auto;
        padding-bottom: 10px;
    }

    .filter-btn {
        white-space: nowrap;
    }
}