/* ==================== 基础重置与变量 ==================== */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #0ea5e9;
    --accent-color: #f43f5e;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-light: #94a3b8;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-dark: #0f172a;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --transition: all 0.3s ease;
    --max-width: 1200px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

/* ==================== 按钮样式 ==================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 500;
    font-size: 0.9375rem;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    box-shadow: 0 4px 14px 0 rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px 0 rgba(99, 102, 241, 0.5);
}

.btn-secondary {
    background: white;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-secondary);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
}

/* ==================== 导航栏 ==================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.logo-icon {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 0.375rem 0.625rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
}

.logo-text {
    color: var(--text-primary);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    padding: 0.5rem 0;
}

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

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition);
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ==================== 主横幅区域 ==================== */
.hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    opacity: 0.5;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    opacity: 0.9;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.hero-actions .btn-primary {
    background: white;
    color: var(--primary-color);
    box-shadow: 0 4px 14px 0 rgba(0, 0, 0, 0.2);
}

.hero-actions .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px 0 rgba(0, 0, 0, 0.3);
}

.hero-actions .btn-secondary {
    background: transparent;
    color: white;
    border-color: rgba(255, 255, 255, 0.5);
}

.hero-actions .btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: white;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-top: 4rem;
    position: relative;
    z-index: 1;
}

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

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.8;
}

/* ==================== 分类区域 ==================== */
.categories {
    padding: 5rem 0;
    background: var(--bg-secondary);
}

.section-title {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.category-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
    border: 1px solid var(--border-color);
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.category-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.category-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.category-card p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* ==================== 资讯区域 ==================== */
.news {
    padding: 5rem 0;
}

.news-header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.news-filter {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background: white;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.875rem;
}

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

.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.news-card {
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.news-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.news-image {
    height: 180px;
    position: relative;
    overflow: hidden;
}

.news-tag {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 500;
}

.news-content {
    padding: 1.5rem;
}

.news-content h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.news-content p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.news-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    font-size: 0.8125rem;
    color: var(--text-light);
}

.news-meta .author {
    font-weight: 500;
    color: var(--text-secondary);
}

.load-more {
    text-align: center;
    margin-top: 3rem;
}

/* ==================== 精选专题 ==================== */
.featured {
    padding: 5rem 0;
    background: var(--bg-secondary);
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.featured-card {
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.featured-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.featured-large {
    grid-column: span 2;
}

.featured-image {
    height: 200px;
    position: relative;
    display: flex;
    align-items: flex-start;
    padding: 1rem;
}

.featured-large .featured-image {
    height: 280px;
}

.featured-tag {
    background: rgba(255, 255, 255, 0.9);
    color: var(--text-primary);
    padding: 0.375rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
}

.featured-content {
    padding: 1.5rem;
}

.featured-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    line-height: 1.4;
}

.featured-content p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: 1rem;
}

.featured-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.8125rem;
    color: var(--text-light);
}

.featured-meta .author {
    font-weight: 500;
    color: var(--text-secondary);
}

/* ==================== 工具区域 ==================== */
.tools {
    padding: 5rem 0;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.tool-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.tool-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.tool-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.tool-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.tool-card p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: 1rem;
}

.tool-link {
    color: var(--primary-color);
    font-weight: 500;
    font-size: 0.9375rem;
}

.tool-link:hover {
    text-decoration: underline;
}

/* ==================== 订阅区域 ==================== */
.subscribe {
    padding: 5rem 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
}

.subscribe-content h2 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.subscribe-content p {
    opacity: 0.9;
    margin-bottom: 2rem;
}

.subscribe-form {
    display: flex;
    gap: 0.75rem;
    max-width: 500px;
    margin: 0 auto 1rem;
}

.subscribe-form input {
    flex: 1;
    padding: 0.875rem 1.25rem;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    outline: none;
}

.subscribe-form input::placeholder {
    color: var(--text-light);
}

.subscribe-form .btn-primary {
    white-space: nowrap;
}

.subscribe-note {
    font-size: 0.8125rem;
    opacity: 0.7;
}

/* ==================== 页脚 ==================== */
.footer {
    background: var(--bg-dark);
    color: white;
    padding: 4rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr repeat(3, 1fr);
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-brand p {
    color: var(--text-light);
    margin: 1rem 0;
    font-size: 0.9375rem;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    color: var(--text-light);
    font-size: 0.875rem;
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

.footer-links h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-links ul li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: var(--text-light);
    font-size: 0.9375rem;
    transition: var(--transition);
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    text-align: center;
    color: var(--text-light);
    font-size: 0.875rem;
}

.icp-info {
    margin-top: 0.5rem;
    font-size: 0.8125rem;
}

.icp-info a {
    color: var(--text-light);
    transition: var(--transition);
}

.icp-info a:hover {
    color: white;
}

/* ==================== 响应式设计 ==================== */

/* 平板设备 */
@media (max-width: 1024px) {
    .featured-large {
        grid-column: span 1;
    }
    
    .featured-large .featured-image {
        height: 200px;
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* 手机设备 */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 2rem;
        gap: 1rem;
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .hero {
        padding: 6rem 0 3rem;
    }
    
    .hero-stats {
        gap: 1.5rem;
        flex-wrap: wrap;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .news-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
    }
    
    .featured-grid {
        grid-template-columns: 1fr;
    }
    
    .subscribe-form {
        flex-direction: column;
    }
    
    /* 手机端隐藏页脚 */
    .footer {
        display: none;
    }
    
    .category-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
}

/* 小屏手机 */
@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-actions {
        flex-direction: column;
    }
    
    .hero-actions .btn {
        width: 100%;
    }
    
    .category-grid {
        grid-template-columns: 1fr;
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .news-filter {
        width: 100%;
        overflow-x: auto;
        flex-wrap: nowrap;
        padding-bottom: 0.5rem;
    }
    
    .filter-btn {
        flex-shrink: 0;
    }
}

/* ==================== 动画效果 ==================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-on-scroll {
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

.animate-on-scroll.visible {
    opacity: 1;
}

/* ==================== 加载状态 ==================== */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 3rem;
}

.loading::after {
    content: '';
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* ==================== 工具类 ==================== */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }