:root {
    --primary: #6366f1;
    --primary-light: #818cf8;
    --primary-dark: #4f46e5;
    --secondary: #f59e0b;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --border: #e2e8f0;
    --shadow: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.03);
    --shadow-lg: 0 4px 12px rgba(0,0,0,0.06), 0 2px 4px rgba(0,0,0,0.04);
    --radius: 14px;
    --radius-sm: 10px;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

[data-theme="dark"] {
    --primary: #818cf8;
    --primary-light: #a5b4fc;
    --primary-dark: #6366f1;
    --bg: #0f172a;
    --card-bg: #1e293b;
    --text: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border: #334155;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-lg: 0 4px 12px rgba(0,0,0,0.4);
    --gradient: linear-gradient(135deg, #818cf8 0%, #a78bfa 100%);
    --gradient-hero: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
}

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

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    transition: var(--transition);
}

a { color: inherit; text-decoration: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; color: inherit; }
input, textarea, select { font-family: inherit; }
img { max-width: 100%; display: block; }

/* ========== Header ========== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}
[data-theme="dark"] .site-header {
    background: rgba(15, 23, 42, 0.85);
}
.site-header.scrolled {
    box-shadow: var(--shadow);
}

.header-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 16px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 700;
}
.logo-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 20px;
}
.logo-text {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 6px;
    list-style: none;
}
.nav-link {
    padding: 8px 16px;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
}
.nav-link:hover, .nav-link.active {
    color: var(--primary);
    background: rgba(99, 102, 241, 0.08);
}

.nav-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border-radius: 6px;
    background: linear-gradient(135deg, rgba(99,102,241,0.12) 0%, rgba(139,92,246,0.12) 100%);
    color: var(--primary);
    font-size: 12px;
    line-height: 1;
    margin-right: 6px;
    vertical-align: middle;
    transition: var(--transition);
}
.nav-link:hover .nav-icon,
.nav-link.active .nav-icon {
    background: var(--gradient);
    color: #fff;
    transform: scale(1.05) rotate(-3deg);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 10px;
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--card-bg);
    border: 1px solid var(--border);
    font-size: 18px;
    transition: var(--transition);
}
.theme-toggle:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: rotate(15deg);
}

.search-toggle {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--card-bg);
    border: 1px solid var(--border);
    font-size: 18px;
    transition: var(--transition);
}
.search-toggle:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.mobile-menu-btn {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: 10px;
    align-items: center;
    justify-content: center;
    background: var(--card-bg);
    border: 1px solid var(--border);
    font-size: 18px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 22px;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    transition: var(--transition);
    text-decoration: none;
    border: 1px solid transparent;
    cursor: pointer;
}
.btn-primary {
    background: var(--gradient);
    color: #fff;
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}
.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}
.btn-outline {
    background: var(--card-bg);
    color: var(--text);
    border-color: var(--border);
}
.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* ========== Hero Section ========== */
.hero {
    background: var(--gradient-hero);
    padding: 80px 24px 60px;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    inset: 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='0.08'%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;
    max-width: 720px;
    margin: 0 auto;
    color: #fff;
}
.hero h1 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}
.hero p {
    font-size: 18px;
    opacity: 0.9;
    margin-bottom: 36px;
}

.hero-search {
    max-width: 600px;
    margin: 0 auto;
    position: relative;
}
.hero-search input {
    width: 100%;
    padding: 18px 60px 18px 24px;
    border-radius: 16px;
    border: none;
    font-size: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
    background: #fff;
    color: #1e293b;
}
.hero-search input:focus {
    outline: none;
}
.hero-search button {
    position: absolute;
    right: 8px;
    top: 50%;
    transform: translateY(-50%);
    width: 46px;
    height: 46px;
    border-radius: 12px;
    background: var(--gradient);
    color: #fff;
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 48px;
    margin-top: 40px;
    flex-wrap: wrap;
}
.hero-stat {
    color: #fff;
    text-align: center;
}
.hero-stat .num {
    font-size: 28px;
    font-weight: 800;
}
.hero-stat .label {
    font-size: 13px;
    opacity: 0.8;
}

/* ========== Main Container ========== */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 40px 24px;
}

/* ========== Category Tabs ========== */
.category-sidebar {
    margin-bottom: 32px;
}
.category-tabs {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 12px;
    scrollbar-width: thin;
}
.category-tab {
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: 10px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
}
.category-tab:hover {
    color: var(--primary);
    border-color: var(--primary-light);
}
.category-tab.active {
    background: var(--gradient);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}
.category-tab .icon { font-size: 16px; }

.category-title-row {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
    color: var(--text, #1e293b);
    font-weight: 700;
    font-size: 16px;
}
.category-title-icon {
    width: 18px;
    height: 18px;
    color: var(--primary);
}
.sub-category-tabs {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}
.sub-category-tab {
    display: inline-flex;
    align-items: center;
    padding: 9px 22px;
    border-radius: 999px;
    background: #f4f4f5;
    color: #52525b;
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    transition: var(--transition);
    border: 1px solid transparent;
    white-space: nowrap;
}
.sub-category-tab:hover {
    background: #e4e4e7;
    color: #18181b;
}
.sub-category-tab.active {
    background: #27272a;
    color: #fff;
    border-color: #27272a;
    box-shadow: 0 8px 18px -6px rgba(0, 0, 0, 0.18);
}

/* ========== Section ========== */
.section {
    margin-bottom: 48px;
}
.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
}
.section-title {
    font-size: 22px;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 10px;
}
.section-title::before {
    content: '';
    width: 4px;
    height: 22px;
    background: var(--gradient);
    border-radius: 2px;
}
.section-more {
    font-size: 14px;
    color: var(--text-muted);
    transition: var(--transition);
}
.section-more:hover { color: var(--primary); }

/* ========== Home Category Header (主分类名 + 右侧子分类标签) ========== */
.home-cat-header {
    align-items: flex-start;
    gap: 20px;
    flex-wrap: wrap;
}
.home-cat-title {
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.5px;
    white-space: nowrap;
    flex-shrink: 0;
}
.home-cat-title::before { display: none; }
.home-cat-tabs {
    flex: 1;
    justify-content: flex-end;
    margin-bottom: 0;
    min-width: 0;
}

/* ========== Cards Grid ========== */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 16px;
}

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

/* 折叠状态：只显示前12个 */
.cards-grid.collapsed > .site-card:nth-child(n+13) {
    display: none !important;
}

.expand-toggle {
    display: flex;
    width: fit-content;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin: 18px auto 0;
    padding: 10px 22px;
    border-radius: 999px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}
.expand-toggle:hover {
    border-color: var(--primary-light);
    color: var(--primary);
    background: rgba(99, 102, 241, 0.06);
}
.expand-toggle .et-arrow {
    display: inline-block;
    transition: transform 0.2s ease;
}
.expand-toggle.expanded .et-arrow {
    transform: rotate(180deg);
}

.site-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 14px 16px;
    border: 1px solid var(--border);
    transition: var(--transition);
    cursor: pointer;
    position: relative;
    overflow: visible;
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 14px;
}
.site-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient);
    opacity: 0;
    transition: var(--transition);
    z-index: 0;
    border-radius: inherit;
}
.site-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}
.site-card:hover::before {
    opacity: 0.04;
}
.site-card:hover .card-title { color: var(--primary); }

.card-icon-large {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #f0f4ff, #e8ecff);
    overflow: hidden;
    font-size: 26px;
    position: relative;
    z-index: 1;
}
[data-theme="dark"] .card-icon-large {
    background: linear-gradient(135deg, #334155, #1e293b);
}
.card-icon-large img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.card-icon-large .icon-emoji { font-size: 26px; }

.card-body { position: relative; z-index: 1; min-width: 0; flex: 1; }
.card-title {
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 4px;
    transition: var(--transition);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.card-desc {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* 悬停详情提示 */
.site-card-tooltip {
    position: fixed;
    z-index: 1000;
    max-width: 300px;
    padding: 12px 14px;
    background: rgba(15, 23, 42, 0.92);
    color: #f8fafc;
    border-radius: 12px;
    font-size: 13px;
    line-height: 1.55;
    box-shadow: 0 16px 40px rgba(0,0,0,0.25);
    pointer-events: none;
    opacity: 0;
    transform: translateY(6px);
    transition: opacity .15s ease, transform .15s ease;
}
.site-card-tooltip.show {
    opacity: 1;
    transform: translateY(0);
}
.site-card-tooltip .tip-title {
    font-weight: 700;
    margin-bottom: 4px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.site-card-tooltip .tip-url {
    font-size: 11px;
    color: #94a3b8;
    margin-bottom: 6px;
    word-break: break-all;
}
.site-card-tooltip .tip-desc {
    color: #e2e8f0;
}

.card-footer {
    margin-top: 14px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    z-index: 1;
}
.card-url {
    font-size: 12px;
    color: var(--text-muted);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    max-width: 70%;
}
.card-clicks {
    font-size: 12px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 4px;
}

/* ========== Featured / Hot Section ========== */
.hot-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 11px;
    font-weight: 600;
    background: linear-gradient(135deg, #fef3c7, #fde68a);
    color: #92400e;
    margin-bottom: 8px;
}

/* ========== Links Section ========== */
.links-section {
    padding: 48px 24px;
    background: var(--card-bg);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}
.links-inner {
    max-width: 1280px;
    margin: 0 auto;
}
.links-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.links-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}
.link-item {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border-radius: 20px;
    background: var(--bg);
    border: 1px solid var(--border);
    font-size: 13px;
    color: var(--text-secondary);
    transition: var(--transition);
}
.link-item:hover {
    color: var(--primary);
    border-color: var(--primary-light);
    background: rgba(99, 102, 241, 0.05);
}
.link-item .link-logo {
    width: 20px;
    height: 20px;
    border-radius: 4px;
    background: var(--border);
    overflow: hidden;
}
.link-item .link-logo img { width: 100%; height: 100%; object-fit: cover; }

/* ========== Footer ========== */
.site-footer {
    padding: 40px 24px;
    text-align: center;
    color: var(--text-muted);
    font-size: 13px;
    border-top: 1px solid var(--border);
}
.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}
.footer-links a {
    color: var(--text-secondary);
    transition: var(--transition);
}
.footer-links a:hover { color: var(--primary); }
.footer-copy { margin-bottom: 8px; }
.footer-icp a { color: var(--text-muted); transition: var(--transition); }
.footer-icp a:hover { color: var(--primary); }

/* ========== Submit Page ========== */
.submit-hero {
    background: var(--gradient-hero);
    padding: 60px 24px;
    text-align: center;
    color: #fff;
}
.submit-hero h1 { font-size: 36px; margin-bottom: 12px; }
.submit-hero p { font-size: 16px; opacity: 0.9; }

.submit-form {
    max-width: 600px;
    margin: -40px auto 0;
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 36px;
    box-shadow: var(--shadow-lg);
    position: relative;
    z-index: 1;
}
.submit-form .form-group { margin-bottom: 20px; }
.submit-form label { display: block; margin-bottom: 6px; font-weight: 500; font-size: 14px; }
.submit-form input, .submit-form textarea, .submit-form select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 14px;
    background: var(--bg);
    color: var(--text);
    transition: var(--transition);
}
.submit-form input:focus, .submit-form textarea:focus, .submit-form select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}
.submit-form textarea { resize: vertical; min-height: 100px; }
.submit-form .submit-btn {
    width: 100%;
    padding: 14px;
    font-size: 16px;
    margin-top: 8px;
}

/* ========== Go Page (Redirect) ========== */
.go-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg);
    padding: 24px;
}
.go-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 48px 40px;
    max-width: 480px;
    width: 100%;
    text-align: center;
    box-shadow: var(--shadow-lg);
}
.go-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 24px;
    background: var(--gradient);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: #fff;
}
.go-card h1 { font-size: 24px; margin-bottom: 8px; }
.go-card .url-display {
    font-size: 14px;
    color: var(--text-secondary);
    word-break: break-all;
    margin-bottom: 24px;
    padding: 12px 16px;
    background: var(--bg);
    border-radius: 10px;
}
.go-countdown {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 24px;
}
.go-countdown .count {
    display: inline-block;
    width: 28px;
    height: 28px;
    line-height: 28px;
    border-radius: 50%;
    background: var(--gradient);
    color: #fff;
    font-weight: 700;
}
.go-actions { display: flex; gap: 12px; justify-content: center; }

/* ========== Search Page ========== */
.search-page {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 24px;
}
.search-header {
    text-align: center;
    margin-bottom: 40px;
}
.search-header h1 { font-size: 32px; margin-bottom: 12px; }
.search-input-large {
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
    position: relative;
}
.search-input-large input {
    width: 100%;
    padding: 16px 20px 16px 56px;
    border-radius: 14px;
    border: 1px solid var(--border);
    font-size: 16px;
    background: var(--card-bg);
    color: var(--text);
}
.search-input-large input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}
.search-input-large .search-icon {
    position: absolute;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 18px;
}

.search-results { margin-top: 32px; }
.search-results h3 {
    margin-bottom: 16px;
    font-size: 16px;
    color: var(--text-secondary);
}
.search-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}
.search-empty .icon { font-size: 48px; margin-bottom: 16px; opacity: 0.5; }

/* ========== Category Page ========== */
.category-header {
    background: var(--card-bg);
    padding: 32px 24px;
    border-radius: var(--radius);
    margin-bottom: 32px;
    display: flex;
    align-items: center;
    gap: 20px;
}
.category-header .cat-icon {
    width: 60px;
    height: 60px;
    border-radius: 16px;
    background: var(--gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: #fff;
}
.category-header .cat-info h1 { font-size: 24px; margin-bottom: 4px; }
.category-header .cat-info p { color: var(--text-secondary); font-size: 14px; }

.category-nav-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 24px;
}
.cat-nav-arrow {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    border-radius: 10px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
    max-width: 45%;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.cat-nav-arrow:hover {
    border-color: var(--primary-light);
    color: var(--primary);
    transform: translateY(-1px);
}
.cat-nav-arrow.disabled {
    opacity: 0.45;
    pointer-events: none;
}

/* ========== Animations ========== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}
.animate-in {
    animation: fadeInUp 0.5s ease forwards;
}

/* ========== Responsive ========== */
@media (max-width: 1024px) {
    .hero h1 { font-size: 36px; }
    .hero-stats { gap: 32px; }
}

@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-menu-btn { display: flex; }
    
    .hero { padding: 48px 20px 40px; }
    .hero h1 { font-size: 28px; }
    .hero p { font-size: 15px; }
    .hero-stats { gap: 24px; }
    .hero-stat .num { font-size: 22px; }
    
    .container { padding: 24px 16px; }
    
    .cards-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 12px;
    }

    .site-card { padding: 16px 12px 14px; gap: 12px; }
    .card-icon-large { width: 44px; height: 44px; font-size: 22px; }
    .card-title { font-size: 14px; }
    .card-desc { font-size: 12px; }
    
    .category-tabs { gap: 6px; }
    .category-tab { padding: 8px 14px; font-size: 13px; }
    
    .section { margin-bottom: 32px; }
    .section-title { font-size: 18px; }
    
    .submit-form { padding: 24px 20px; margin: -20px 16px 0; }
    .submit-hero h1 { font-size: 24px; }
    
    .go-card { padding: 36px 24px; }
    
    .footer-links { gap: 16px; }
}

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

/* ========== Scrollbar ========== */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ========== Selection ========== */
::selection {
    background: rgba(99, 102, 241, 0.2);
    color: var(--primary);
}

/* ========== Back to Top ========== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--gradient);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 90;
}
.back-to-top.show {
    opacity: 1;
    visibility: visible;
}
.back-to-top:hover {
    transform: translateY(-3px);
}

/* ========== Loading Skeleton ========== */
.skeleton {
    background: linear-gradient(90deg, var(--bg) 25%, var(--border) 50%, var(--bg) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}
@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ========== 左右式布局（app-layout） ========== */
.app-layout {
    display: flex;
    gap: 28px;
    max-width: 1320px;
    margin: 0 auto;
    padding: 28px 20px 40px;
    align-items: flex-start;
}
.sidebar {
    flex: 0 0 250px;
    width: 250px;
    position: sticky;
    top: 88px;
    align-self: flex-start;
    max-height: calc(100vh - 110px);
    overflow-y: auto;
    border-radius: 18px;
    background: #f8fafc;
    border: 1px solid var(--border);
    box-shadow: 0 10px 30px -18px rgba(0, 0, 0, 0.12);
}
.sidebar-inner { padding: 18px 14px; }
.sidebar-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 6px 10px 16px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 14px;
}
.sidebar-logo .logo-emoji { font-size: 24px; line-height: 1; }
.sidebar-logo img { width: 32px; height: 32px; border-radius: 10px; object-fit: cover; }
.sidebar-logo-text {
    font-size: 15px;
    font-weight: 700;
    color: var(--text);
    letter-spacing: 0.2px;
}
.sidebar-title {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 1px;
    color: var(--text-muted);
    text-transform: uppercase;
    padding: 4px 12px 10px;
}
.sidebar-nav { display: flex; flex-direction: column; gap: 3px; }
.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    border-radius: 12px;
    color: var(--text);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    transition: var(--transition, .2s);
}
.nav-item:hover { background: rgba(99, 102, 241, 0.08); color: #6366f1; }
.nav-item.active {
    background: #ef4444;
    color: #fff;
    box-shadow: 0 6px 16px -6px rgba(239, 68, 68, 0.45);
}
.nav-item-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    color: var(--text-muted);
    transition: var(--transition, .2s);
}
.nav-item-icon-emoji {
    width: auto;
    height: auto;
    font-size: 18px;
    line-height: 1;
    color: var(--text);
}
.nav-item:hover .nav-item-icon,
.nav-item.active .nav-item-icon { color: currentColor; }
.nav-item-text { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nav-item-row {
    display: flex;
    align-items: center;
    gap: 2px;
}
.nav-item-row .nav-item { flex: 1; min-width: 0; }
.nav-fold-btn {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-muted);
    cursor: pointer;
    transition: transform .2s ease, background .2s ease, color .2s ease;
    flex-shrink: 0;
}
.nav-fold-btn:hover {
    background: rgba(99, 102, 241, 0.08);
    color: #6366f1;
}
.nav-fold-btn .fold-arrow {
    width: 14px;
    height: 14px;
    display: block;
    transition: transform .2s ease;
}
.nav-fold-btn.collapsed .fold-arrow {
    transform: rotate(-90deg);
}
.nav-sub.collapsed {
    display: none;
}
.nav-group { margin-bottom: 2px; }
.nav-sub {
    display: flex;
    flex-direction: column;
    gap: 2px;
    margin: 2px 0 6px 34px;
    padding-left: 12px;
    border-left: 1px solid var(--border);
}
.nav-sub-item {
    padding: 7px 12px;
    border-radius: 10px;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 13px;
    transition: var(--transition, .2s);
}
.nav-sub-item:hover { background: rgba(99, 102, 241, 0.08); color: #6366f1; }
.nav-sub-item.active { color: #6366f1; background: rgba(99, 102, 241, 0.12); font-weight: 700; }
.content { flex: 1; min-width: 0; }

.module-desc {
    margin: -6px 0 16px;
    font-size: 13px;
    color: var(--text-muted, #64748b);
}

/* 移动端：侧边栏变为抽屉 */
@media (max-width: 860px) {
    .app-layout { flex-direction: column; gap: 18px; padding: 18px 12px 32px; }
    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        bottom: 0;
        width: 260px;
        max-height: none;
        border-radius: 0;
        transform: translateX(-105%);
        transition: transform .28s cubic-bezier(.2,.8,.2,1);
        z-index: 200;
        box-shadow: 0 0 40px rgba(0,0,0,.25);
    }
    .sidebar.open { transform: translateX(0); }
    .mobile-menu-btn { display: inline-flex !important; }
}
@media (min-width: 861px) {
    .mobile-menu-btn { display: none; }
}

/* ========== 新版顶栏（汉堡 + Logo + 搜索 + 申请收录） ========== */
.header-left {
    display: flex;
    align-items: center;
    gap: 14px;
}
.sidebar-toggle {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    cursor: pointer;
    transition: var(--transition);
}
.sidebar-toggle span {
    display: block;
    width: 18px;
    height: 2px;
    background: var(--text-secondary);
    border-radius: 2px;
    transition: var(--transition);
}
.sidebar-toggle:hover { border-color: var(--primary); }
.sidebar-toggle:hover span { background: var(--primary); }
.logo-icon.logo-img {
    background: transparent;
    padding: 4px;
}
.logo-icon.logo-img img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}
.submit-header-btn {
    padding: 9px 18px;
    font-size: 13px;
    border-radius: 10px;
}

/* ========== 侧边栏折叠 ========== */
.app-layout.sidebar-collapsed .sidebar {
    width: 72px;
    flex-basis: 72px;
}
.app-layout.sidebar-collapsed .sidebar-logo-text,
.app-layout.sidebar-collapsed .sidebar-nav span,
.app-layout.sidebar-collapsed .nav-sub,
.app-layout.sidebar-collapsed .sidebar-title {
    display: none;
}
.app-layout.sidebar-collapsed .sidebar-logo {
    justify-content: center;
    padding: 0;
}
.app-layout.sidebar-collapsed .sidebar-logo img,
.app-layout.sidebar-collapsed .sidebar-logo .logo-emoji {
    width: 40px;
    height: 40px;
}
.app-layout.sidebar-collapsed .nav-item {
    justify-content: center;
    padding: 10px;
}
.app-layout.sidebar-collapsed .nav-item-icon {
    width: 22px;
    height: 22px;
}
.app-layout.sidebar-collapsed .nav-item-icon-emoji {
    font-size: 22px;
}
.app-layout.sidebar-collapsed .sidebar-bottom {
    justify-content: center;
}

.sidebar-bottom {
    margin-top: auto;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
}
.sidebar-bottom .theme-toggle {
    position: static;
    width: 38px;
    height: 38px;
    border-radius: 10px;
    background: var(--bg);
    border: 1px solid var(--border);
}

/* ========== 右侧悬浮联系栏 ========== */
.contact-float {
    position: fixed;
    right: 18px;
    bottom: 90px;
    z-index: 95;
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.contact-btn {
    width: 46px;
    height: 46px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--card-bg);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    color: var(--text-secondary);
    font-size: 18px;
    cursor: pointer;
    transition: var(--transition);
    opacity: 0;
    transform: translateY(10px);
    animation: fadeInUp .4s ease forwards;
}
.contact-btn:nth-child(1) { animation-delay: .05s; }
.contact-btn:nth-child(2) { animation-delay: .1s; }
.contact-btn:nth-child(3) { animation-delay: .15s; }
.contact-btn:nth-child(4) { animation-delay: .2s; }
.contact-btn:nth-child(5) { animation-delay: .25s; }
.contact-btn:nth-child(6) { animation-delay: .3s; }
.contact-btn:nth-child(7) { animation-delay: .35s; }
.contact-btn.show { opacity: 1; transform: translateY(0); }
.contact-btn:hover {
    transform: translateY(-3px) scale(1.05);
    border-color: var(--primary);
    color: var(--primary);
}
.contact-btn img {
    width: 28px;
    height: 28px;
    object-fit: contain;
    border-radius: 6px;
}
.contact-float .theme-toggle {
    margin-top: 6px;
}

/* 返回顶部默认显示 */
#backToTopBtn { opacity: 1; transform: none; }
#backToTopBtn:not(.show) { opacity: 0; visibility: hidden; transform: translateY(10px); }

/* 联系信息弹窗 */
.contact-popup-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.45);
    backdrop-filter: blur(6px);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}
.contact-popup {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 28px;
    max-width: 320px;
    width: 100%;
    text-align: center;
    box-shadow: var(--shadow-lg);
    position: relative;
}
.contact-popup-close {
    position: absolute;
    top: 12px;
    right: 12px;
    width: 30px;
    height: 30px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg);
    color: var(--text-secondary);
    font-size: 20px;
    cursor: pointer;
}
.contact-popup-icon {
    width: 56px;
    height: 56px;
    border-radius: 16px;
    background: linear-gradient(135deg, #eef2ff, #faf5ff);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    margin: 0 auto 14px;
}
.contact-popup-title {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 16px;
}
.contact-popup-value {
    background: var(--bg);
    padding: 12px 16px;
    border-radius: 12px;
    font-size: 15px;
    font-weight: 600;
    word-break: break-all;
    margin-bottom: 14px;
    color: var(--text);
}
.contact-popup-image {
    margin-bottom: 14px;
}
.contact-popup-image img {
    max-width: 100%;
    max-height: 240px;
    border-radius: 14px;
    border: 1px solid var(--border);
    background: #fff;
    padding: 6px;
    box-shadow: var(--shadow-sm, 0 2px 8px rgba(0,0,0,.06));
}
.contact-popup-copy {
    width: 100%;
    justify-content: center;
}
.contact-btn .contact-thumb {
    width: 30px;
    height: 30px;
    object-fit: contain;
    border-radius: 8px;
    background: #fff;
}

/* 适配窄屏：顶栏简化 */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .logo-text { font-size: 16px; }
    .submit-header-btn { padding: 8px 12px; font-size: 12px; }
    .contact-float { right: 12px; bottom: 80px; }
    .contact-btn { width: 42px; height: 42px; font-size: 16px; }
    .contact-btn .contact-thumb { width: 26px; height: 26px; }
}

/* 移动端抽屉保持原逻辑 */
@media (max-width: 860px) {
    .app-layout.sidebar-collapsed .sidebar { width: 260px; flex-basis: 260px; }
    .app-layout.sidebar-collapsed .sidebar-logo-text,
    .app-layout.sidebar-collapsed .sidebar-nav span,
    .app-layout.sidebar-collapsed .nav-sub,
    .app-layout.sidebar-collapsed .sidebar-title { display: block; }
    .app-layout.sidebar-collapsed .nav-item { justify-content: flex-start; padding: 10px 12px; }
    .app-layout.sidebar-collapsed .nav-item-icon { font-size: 16px; }
}

/* ========== Dark mode overrides ========== */
[data-theme="dark"] .sidebar {
    background: #1e293b;
    border-color: var(--border);
    box-shadow: 0 10px 30px -18px rgba(0, 0, 0, 0.5);
}
[data-theme="dark"] .sidebar-logo { border-bottom-color: var(--border); }
[data-theme="dark"] .sidebar-logo-text { color: var(--text); }
[data-theme="dark"] .nav-item { color: var(--text); }
[data-theme="dark"] .nav-item:hover { background: rgba(129, 140, 248, 0.12); color: var(--primary-light); }
[data-theme="dark"] .nav-item.active { background: #ef4444; color: #fff; }
[data-theme="dark"] .nav-item-icon { color: var(--text-muted); }
[data-theme="dark"] .nav-item.active .nav-item-icon { color: #fff; }
[data-theme="dark"] .nav-fold-btn { color: var(--text-muted); }
[data-theme="dark"] .nav-fold-btn:hover { background: rgba(129, 140, 248, 0.12); color: var(--primary-light); }
[data-theme="dark"] .nav-sub { border-left-color: var(--border); }
[data-theme="dark"] .nav-sub-item { color: var(--text-muted); }
[data-theme="dark"] .nav-sub-item:hover { background: rgba(129, 140, 248, 0.12); color: var(--primary-light); }
[data-theme="dark"] .nav-sub-item.active { color: #fff; background: rgba(239, 68, 68, 0.22); }
[data-theme="dark"] .sub-category-tab { background: #334155; color: #cbd5e1; }
[data-theme="dark"] .sub-category-tab:hover { background: #475569; color: #f1f5f9; }
[data-theme="dark"] .sub-category-tab.active { background: #ef4444; color: #fff; border-color: #ef4444; }
[data-theme="dark"] .category-title-row { color: var(--text); }
[data-theme="dark"] .category-title-icon { color: var(--primary); }