/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #6366f1;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --background: #f9fafb;
    --card-bg: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 0.5rem;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* 头部样式 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 1rem 0;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    background: linear-gradient(135deg, #3b82f6, #8b5cf6);
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.logo-text h1 {
    background: linear-gradient(135deg, #2563eb, #7c3aed);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1.2;
}

.logo-text p {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.header-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.date {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* 主内容区 */
.main-content {
    padding-top: 6rem;
    padding-bottom: 4rem;
}

.hero {
    text-align: center;
    margin-bottom: 3rem;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #2563eb, #7c3aed, #ec4899);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* 搜索框 */
.search-container {
    position: relative;
    max-width: 600px;
    margin: 0 auto;
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
}

.search-input {
    width: 100%;
    padding: 1rem 1rem 1rem 3rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 9999px;
    background: white;
    transition: all 0.3s;
    box-shadow: var(--shadow-md);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* 分类导航 */
.category-nav {
    margin-bottom: 2rem;
}

.category-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    background: white;
    padding: 0.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.category-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border: none;
    background: transparent;
    border-radius: calc(var(--radius) - 2px);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.category-btn:hover {
    background: var(--background);
    color: var(--text-primary);
}

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

.cat-count {
    background: rgba(0, 0, 0, 0.1);
    padding: 0.125rem 0.5rem;
    border-radius: 9999px;
    font-size: 0.75rem;
}

/* 筛选状态 */
.filter-status {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.filter-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.filter-icon {
    width: 16px;
    height: 16px;
}

/* 资源网格 */
.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

/* 资源卡片 */
.resource-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    transition: all 0.3s;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
}

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

.resource-card.hidden {
    display: none;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.75rem;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin: 0;
    color: var(--text-primary);
    line-height: 1.3;
}

.resource-card:hover .card-title {
    color: var(--primary-color);
}

.badge {
    padding: 0.25rem 0.5rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
    white-space: nowrap;
}

.badge-featured {
    background: #fef3c7;
    color: #d97706;
}

.card-description {
    color: var(--text-secondary);
    font-size: 0.875rem;
    line-height: 1.6;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    min-height: 42px;
}

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tag {
    padding: 0.25rem 0.5rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    background: var(--background);
    color: var(--text-secondary);
}

.tag-category {
    background: #dbeafe;
    color: #1d4ed8;
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    border: none;
    border-radius: var(--radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    width: 100%;
    margin-top: auto;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-icon {
    width: 16px;
    height: 16px;
}

/* 推荐区域 */
.featured-section {
    margin-top: 4rem;
}

.featured-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.featured-header h3 {
    font-size: 1.5rem;
    font-weight: 700;
}

.featured-card {
    border: 2px solid #fbbf24;
}

/* 页脚 */
.footer {
    background: var(--background);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0;
    margin-top: 4rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.footer-section p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

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

.footer-section li {
    color: var(--text-secondary);
    font-size: 0.875rem;
    padding: 0.25rem 0;
    cursor: pointer;
    transition: color 0.2s;
}

.footer-section li:hover {
    color: var(--text-primary);
}

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

.footer-bottom p {
    margin: 0.25rem 0;
}

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

.icp {
    margin-top: 0.5rem;
    font-size: 0.8125rem;
    color: var(--text-secondary);
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    background: white;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.empty-state h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.empty-state p {
    color: var(--text-secondary);
}

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

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

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

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

    .header-info {
        display: none;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }
}

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

/* 动画 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.resource-card {
    animation: fadeIn 0.3s ease-out;
}