/* ============================================
   51吃瓜网 - 主样式表
   ============================================ */

/* --- CSS Variables --- */
:root {
    --color-primary: #e74c3c;
    --color-primary-dark: #c0392b;
    --color-accent: #2ecc71;
    --color-bg: #f5f6fa;
    --color-surface: #ffffff;
    --color-text: #2c3e50;
    --color-text-secondary: #7f8c8d;
    --color-border: #ecf0f1;
    --color-card-hover: #fafbfc;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
    --radius: 12px;
    --radius-sm: 8px;
    --max-width: 1200px;
    --header-height: 64px;
    --transition: 0.2s ease;
}

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
                 "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
a { color: var(--color-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-primary-dark); }
img { max-width: 100%; height: auto; display: block; }

/* --- Container --- */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* --- Header --- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--color-surface);
    box-shadow: var(--shadow-sm);
    border-bottom: 1px solid var(--color-border);
}
.header-inner {
    display: flex;
    align-items: center;
    height: var(--header-height);
    gap: 24px;
}
.site-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 20px;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    white-space: nowrap;
}
.logo-icon { font-size: 28px; }
.site-nav {
    display: flex;
    gap: 4px;
    flex: 1;
    overflow-x: auto;
    scrollbar-width: none;
}
.site-nav::-webkit-scrollbar { display: none; }
.nav-link {
    padding: 8px 14px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-text-secondary);
    white-space: nowrap;
    transition: all var(--transition);
}
.nav-link:hover, .nav-link.active {
    background: var(--color-primary);
    color: white;
}
.header-search {
    display: flex;
    align-items: center;
}
.header-search form {
    display: flex;
    background: var(--color-bg);
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid var(--color-border);
}
.header-search input {
    border: none;
    background: transparent;
    padding: 8px 16px;
    font-size: 14px;
    outline: none;
    width: 180px;
    color: var(--color-text);
}
.header-search button {
    border: none;
    background: var(--color-primary);
    color: white;
    padding: 8px 16px;
    font-size: 14px;
    cursor: pointer;
    transition: background var(--transition);
}
.header-search button:hover { background: var(--color-primary-dark); }

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--color-text);
}
.mobile-nav {
    display: none;
    flex-wrap: wrap;
    gap: 8px;
    padding: 12px 20px;
    border-top: 1px solid var(--color-border);
}
.mobile-nav.open { display: flex; }
.mobile-nav .nav-link { font-size: 14px; }

/* --- Page Hero --- */
.page-hero {
    text-align: center;
    padding: 40px 0 30px;
}
.page-hero h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
}
.page-hero p {
    color: var(--color-text-secondary);
    font-size: 15px;
}

/* --- Ads (一行左右 2 个) --- */
.ad-row-container {
    display: flex;
    gap: 12px;
    margin: 0 0 24px;
    width: 100%;
}
.article-header .ad-row-container {
    margin: 16px 0 12px;
}
.ad-slot {
    flex: 1;
    background: var(--color-bg);
    border-radius: 10px;
    overflow: hidden;
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
}
.ad-slot img {
    width: 100%;
    height: auto;
    object-fit: cover;
    display: block;
}

/* --- Article Grid --- */
.article-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
    padding-bottom: 40px;
}

/* --- Article Card --- */
.article-card {
    background: var(--color-surface);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition), box-shadow var(--transition);
}
.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}
.card-cover {
    position: relative;
    display: block;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background: var(--color-border);
}
.card-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}
.article-card:hover .card-cover img {
    transform: scale(1.05);
}
.card-category {
    position: absolute;
    top: 12px;
    left: 12px;
    background: var(--color-primary);
    color: white;
    font-size: 12px;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 12px;
}
.card-body { padding: 16px 20px 20px; }
.card-title {
    font-size: 17px;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 8px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.card-title a { color: var(--color-text); }
.card-title a:hover { color: var(--color-primary); }
.card-excerpt {
    font-size: 14px;
    color: var(--color-text-secondary);
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    margin-bottom: 12px;
}
.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
}
.card-date { color: var(--color-text-secondary); }
.card-readmore {
    font-weight: 500;
    font-size: 13px;
}

/* --- Pagination --- */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    padding: 20px 0 50px;
}
.page-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 40px;
    height: 40px;
    padding: 0 12px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    transition: all var(--transition);
}
.page-link:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}
.page-link.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* --- Article Detail --- */
.article-detail {
    max-width: 800px;
    margin: 0 auto;
    padding: 30px 0 60px;
}
.article-breadcrumb {
    font-size: 13px;
    color: var(--color-text-secondary);
    margin-bottom: 16px;
}
.article-breadcrumb a { color: var(--color-text-secondary); }
.article-breadcrumb a:hover { color: var(--color-primary); }
.article-title {
    font-size: 28px;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 16px;
}
.article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 14px;
    color: var(--color-text-secondary);
    padding-bottom: 20px;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 30px;
}
.tag {
    display: inline-block;
    background: var(--color-bg);
    color: var(--color-text-secondary);
    padding: 2px 10px;
    border-radius: 12px;
    font-size: 12px;
    margin: 0 2px;
}
.article-cover {
    margin-bottom: 30px;
    border-radius: var(--radius);
    overflow: hidden;
}
.article-cover img { width: 100%; }
.article-content {
    font-size: 16px;
    line-height: 1.8;
    color: var(--color-text);
}
.article-content h2 { font-size: 22px; margin: 32px 0 16px; }
.article-content h3 { font-size: 18px; margin: 24px 0 12px; }
.article-content p { margin-bottom: 16px; }
.article-content img {
    border-radius: var(--radius-sm);
    margin: 16px 0;
}
.article-content blockquote {
    border-left: 4px solid var(--color-primary);
    padding: 12px 20px;
    margin: 16px 0;
    background: var(--color-bg);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    color: var(--color-text-secondary);
}
.article-content pre {
    background: #1e1e1e;
    color: #d4d4d4;
    padding: 16px 20px;
    border-radius: var(--radius-sm);
    overflow-x: auto;
    margin: 16px 0;
}
.article-content code {
    font-family: "SF Mono", "Fira Code", monospace;
    font-size: 14px;
}
.article-content ul, .article-content ol {
    padding-left: 24px;
    margin-bottom: 16px;
}
.article-content li { margin-bottom: 8px; }
.article-content a {
    color: var(--color-primary);
    text-decoration: underline;
    text-decoration-color: rgba(231,76,60,0.3);
}
.article-content a:hover { text-decoration-color: var(--color-primary); }
.article-content hr {
    border: none;
    height: 1px;
    background: var(--color-border);
    margin: 32px 0;
}
.article-footer {
    margin-top: 40px;
    padding-top: 24px;
    border-top: 1px solid var(--color-border);
}
.article-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.tag-lg {
    background: var(--color-bg);
    color: var(--color-text-secondary);
    padding: 6px 16px;
    border-radius: 16px;
    font-size: 13px;
}
.article-nav { display: flex; gap: 12px; }
.btn {
    display: inline-flex;
    align-items: center;
    padding: 10px 24px;
    background: var(--color-primary);
    color: white;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    transition: background var(--transition);
}
.btn:hover { background: var(--color-primary-dark); color: white; }

/* --- Empty State --- */
.empty-state {
    text-align: center;
    padding: 80px 20px;
    color: var(--color-text-secondary);
}
.empty-state h2 { font-size: 48px; margin-bottom: 12px; }
.empty-state p { margin-bottom: 24px; }

/* --- Search Form (Large) --- */
.search-form-lg {
    display: flex;
    max-width: 500px;
    margin: 0 auto;
    border-radius: 24px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}
.search-form-lg input {
    flex: 1;
    border: none;
    padding: 14px 24px;
    font-size: 16px;
    outline: none;
}
.search-form-lg .btn { border-radius: 0 24px 24px 0; }

/* --- Footer --- */
.site-footer {
    margin-top: auto;
    padding: 30px 0;
    text-align: center;
    border-top: 1px solid var(--color-border);
}
.footer-disclaimer {
    font-size: 13px;
    color: var(--color-text-secondary);
    margin-bottom: 8px;
}
.footer-copy { font-size: 12px; color: #bdc3c7; }

/* --- Responsive --- */
@media (max-width: 768px) {
    .site-nav { display: none; }
    .header-search { display: none; }
    .mobile-menu-toggle { display: block; }
    .article-grid { grid-template-columns: 1fr; gap: 16px; }
    .ad-row-container { gap: 8px; }
    .page-hero h1 { font-size: 22px; }
    .article-title { font-size: 22px; }
    .article-meta { gap: 8px; font-size: 13px; }
    .header-inner { gap: 12px; }
}
@media (min-width: 769px) and (max-width: 1024px) {
    .article-grid { grid-template-columns: repeat(2, 1fr); }
}

/* --- Lazy Load Placeholder --- */
.card-cover img[data-src] {
    background: linear-gradient(135deg, #ecf0f1 25%, #f5f6fa 50%, #ecf0f1 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}
@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* --- Default Cover SVG Placeholder --- */
.card-cover img[src*="default-cover"] {
    background: linear-gradient(135deg, var(--color-primary) 0%, #e67e22 100%);
    min-height: 180px;
}