/* ===== 全局样式 ===== */
:root {
    --primary: #667eea;
    --primary-dark: #5a67d8;
    --bg: #f8f9fa;
    --bg-card: #ffffff;
    --text: #2d3748;
    --text-muted: #718096;
    --border: #e2e8f0;
    --shadow: 0 10px 30px rgba(0,0,0,0.08);
    --radius: 16px;
    --transition: 0.3s ease;
}

[data-theme="dark"] {
    --bg: #1a202c;
    --bg-card: #2d3748;
    --text: #e2e8f0;
    --text-muted: #a0aec0;
    --border: #4a5568;
    --shadow: 0 10px 30px rgba(0,0,0,0.3);
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background var(--transition), color var(--transition);
}

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

/* ===== 头部 ===== */
.site-header {
    background: var(--bg-card);
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
}

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

.logo a {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
}

.main-nav ul {
    list-style: none;
    display: flex;
    gap: 25px;
    align-items: center;
}

.main-nav a {
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    transition: color var(--transition);
}

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

.nav-extra {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-left: 20px;
}

.icon-btn {
    background: none;
    border: 2px solid var(--border);
    color: var(--text);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}

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

.hamburger {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text);
    cursor: pointer;
}

/* ===== 按钮 ===== */
.btn {
    display: inline-block;
    padding: 10px 24px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all var(--transition);
    border: none;
    cursor: pointer;
}

.btn-sm { padding: 6px 16px; font-size: 0.85rem; }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 5px 15px rgba(102,126,234,0.4); }
.btn-outline { background: transparent; border: 2px solid var(--primary); color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: white; }
.btn-success { background: #48bb78; color: white; }
.btn-danger { background: #f56565; color: white; }
.btn-block { width: 100%; }

/* ===== Hero ===== */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, #764ba2 100%);
    color: white;
    padding: 100px 0 80px;
    text-align: center;
}

.hero h1 { font-size: 3rem; margin-bottom: 15px; }
.hero p { font-size: 1.2rem; opacity: 0.9; max-width: 600px; margin: 0 auto 30px; }

.hero-search form {
    display: flex;
    max-width: 500px;
    margin: 0 auto;
    background: white;
    border-radius: 50px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0,0,0,0.2);
}

.hero-search input {
    flex: 1;
    padding: 15px 20px;
    border: none;
    outline: none;
    font-size: 1rem;
}

.hero-search button {
    padding: 15px 30px;
    background: var(--primary);
    color: white;
    border: none;
    cursor: pointer;
    font-weight: 600;
    transition: background var(--transition);
}

.hero-search button:hover { background: var(--primary-dark); }

.hero-stats {
    margin-top: 30px;
    display: flex;
    justify-content: center;
    gap: 30px;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* ===== 分类 ===== */
.categories { padding: 60px 0; }
.categories h2 { text-align: center; margin-bottom: 30px; font-size: 2rem; }

.cat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 15px;
}

.cat-card {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    transition: all var(--transition);
    box-shadow: var(--shadow);
}

.cat-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
    color: var(--primary);
}

/* ===== 卡片网格 ===== */
.featured { padding: 40px 0; }
.featured h2 { text-align: center; margin-bottom: 30px; font-size: 2rem; }

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 25px;
}

.card {
    background: var(--bg-card);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all var(--transition);
}

.card:hover { transform: translateY(-8px); box-shadow: 0 20px 40px rgba(0,0,0,0.12); }

.card-img {
    height: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: white;
}

.card-body { padding: 20px; }

.card-cat {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.card-body h3 { font-size: 1.2rem; margin-bottom: 8px; }
.card-body p { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 12px; }

.card-meta {
    display: flex;
    gap: 15px;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 15px;
}

/* ===== 热力图 ===== */
.heatmap { padding: 50px 0; }
.heatmap h2 { text-align: center; margin-bottom: 25px; }

.heatmap-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.heat-item {
    background: var(--primary);
    color: white;
    padding: 10px 20px;
    border-radius: 50px;
    font-size: 0.9rem;
    cursor: default;
    transition: transform var(--transition);
}

.heat-item:hover { transform: scale(1.05); }

/* ===== 分享 ===== */
.share-section { padding: 50px 0; text-align: center; }
.share-section h2 { margin-bottom: 20px; }

.share-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.share-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    color: white;
    font-size: 1.5rem;
    transition: all var(--transition);
    text-decoration: none;
}

.share-btn.twitter { background: #1da1f2; }
.share-btn.facebook { background: #1877f2; }
.share-btn.linkedin { background: #0a66c2; }
.share-btn.weibo { background: #e6162d; }
.share-btn:hover { transform: scale(1.15); }

/* ===== 页脚 ===== */
.site-footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    padding: 50px 0 20px;
    margin-top: 60px;
}

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

.footer-col h4 { margin-bottom: 15px; font-size: 1.1rem; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 8px; }
.footer-col a { color: var(--text-muted); text-decoration: none; }
.footer-col a:hover { color: var(--primary); }

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-bottom a { color: var(--primary); text-decoration: none; }

/* ===== 登录页 ===== */
.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary), #764ba2);
}

.login-box {
    background: var(--bg-card);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 400px;
}

.login-box h2 { text-align: center; margin-bottom: 25px; color: var(--text); }

/* ===== 表单 ===== */
.form-group { margin-bottom: 18px; }
.form-group label { display: block; margin-bottom: 6px; font-weight: 500; }
.form-group input, .form-group textarea, .form-group select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: 10px;
    font-size: 1rem;
    background: var(--bg);
    color: var(--text);
    transition: border var(--transition);
}

.form-group input:focus, .form-group textarea:focus {
    border-color: var(--primary);
    outline: none;
}

/* ===== 管理后台 ===== */
.admin-body {
    background: var(--bg);
}

.admin-container {
    display: flex;
    min-height: 100vh;
}

.admin-sidebar {
    width: 250px;
    background: var(--bg-card);
    border-right: 1px solid var(--border);
    padding: 30px 20px;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    overflow-y: auto;
}

.admin-sidebar h2 { margin-bottom: 30px; font-size: 1.3rem; color: var(--primary); }
.admin-sidebar ul { list-style: none; }
.admin-sidebar li { margin-bottom: 10px; }
.admin-sidebar a {
    display: block;
    padding: 12px 16px;
    border-radius: 10px;
    color: var(--text);
    text-decoration: none;
    transition: all var(--transition);
}

.admin-sidebar a:hover, .admin-sidebar a.active {
    background: var(--primary);
    color: white;
}

.admin-main {
    margin-left: 250px;
    flex: 1;
    padding: 30px;
}

.admin-header {
    margin-bottom: 30px;
}

.admin-header h1 { font-size: 1.8rem; }
.admin-header p { color: var(--text-muted); }

.admin-section { display: none; }
.admin-section.active { display: block; }

.stats-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--bg-card);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    font-size: 1.2rem;
}

.stat-card i { font-size: 2rem; color: var(--primary); display: block; margin-bottom: 10px; }

.table-responsive { overflow-x: auto; }

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-card);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

th, td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th { background: var(--primary); color: white; }

.alert {
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 20px;
}

.alert-success { background: #c6f6d5; color: #22543d; }
.alert-error { background: #fed7d7; color: #9b2c2c; }

.heatmap-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.heat-tag {
    padding: 8px 16px;
    border-radius: 50px;
    color: white;
    font-size: 0.85rem;
}

/* ===== 内页通用 ===== */
.page-hero {
    background: linear-gradient(135deg, var(--primary), #764ba2);
    color: white;
    padding: 60px 0;
    text-align: center;
}

.page-hero h1 { font-size: 2.5rem; margin-bottom: 10px; }

.page-content { padding: 50px 0; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .main-nav {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 80%;
        height: 100vh;
        background: var(--bg-card);
        flex-direction: column;
        padding: 30px;
        transition: left 0.3s;
        box-shadow: 2px 0 10px rgba(0,0,0,0.1);
    }

    .main-nav.open { left: 0; }

    .main-nav ul { flex-direction: column; gap: 15px; }
    .nav-extra { margin-left: 0; margin-top: 20px; }

    .hamburger { display: block; }

    .hero h1 { font-size: 2rem; }
    .hero-search form { flex-direction: column; border-radius: 20px; }
    .hero-search input { border-radius: 20px 20px 0 0; }
    .hero-search button { border-radius: 0 0 20px 20px; }

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

    .admin-sidebar {
        width: 100%;
        position: relative;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border);
    }

    .admin-main { margin-left: 0; }

    .admin-container { flex-direction: column; }
}