/* AIQuant.pro — Dark theme SEO site */

:root {
    --bg: #0d1117;
    --bg-card: #161b22;
    --bg-header: #0d1117;
    --border: #30363d;
    --text: #c9d1d9;
    --text-muted: #8b949e;
    --accent: #58a6ff;
    --accent-hover: #79c0ff;
    --green: #3fb950;
    --orange: #d2991d;
    --red: #f85149;
    --radius: 8px;
    --max-width: 800px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* Header */
.site-header {
    background: var(--bg-header);
    border-bottom: 1px solid var(--border);
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent);
    text-decoration: none;
    letter-spacing: -0.5px;
}
.logo span { color: var(--text); font-weight: 400; }

.site-header nav a {
    color: var(--text-muted);
    text-decoration: none;
    margin-left: 24px;
    font-size: 0.9rem;
    transition: color 0.2s;
}

.site-header nav a:hover { color: var(--text); }

/* Hero */
.hero {
    text-align: center;
    padding: 80px 20px 60px;
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent), var(--green));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 16px;
}

.hero-desc {
    font-size: 1.15rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto 8px;
}

.hero-sub {
    font-size: 0.95rem;
    color: var(--text-muted);
    opacity: 0.7;
}

/* Articles Grid */
.articles-section { padding: 40px 0 80px; }

.articles-section h2 {
    font-size: 1.3rem;
    margin-bottom: 32px;
    color: var(--text);
}

.article-grid {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.article-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    transition: border-color 0.2s;
}

.article-card:hover { border-color: var(--accent); }

.article-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.tags { display: flex; gap: 6px; }
.tag {
    background: rgba(88, 166, 255, 0.1);
    color: var(--accent);
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
}

.article-card h3 { margin-bottom: 8px; }
.article-card h3 a { color: var(--text); text-decoration: none; }
.article-card h3 a:hover { color: var(--accent); }

.article-summary {
    color: var(--text-muted);
    font-size: 0.92rem;
    margin-bottom: 12px;
}

.read-more {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.88rem;
    font-weight: 500;
}

.read-more:hover { color: var(--accent-hover); }

/* Single Article */
.single-article { padding: 60px 0 80px; }

.article-header { margin-bottom: 40px; }
.article-header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 16px;
    line-height: 1.3;
}

.article-body {
    font-size: 1.05rem;
    line-height: 1.85;
}

.article-body h2 {
    font-size: 1.4rem;
    margin: 40px 0 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.article-body h3 { font-size: 1.15rem; margin: 32px 0 12px; }
.article-body h4 { font-size: 1.05rem; margin: 24px 0 8px; }

.article-body p { margin-bottom: 18px; }

.article-body code {
    background: var(--bg);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    border: 1px solid var(--border);
}

.article-body pre {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    overflow-x: auto;
    margin-bottom: 20px;
    font-size: 0.88rem;
    line-height: 1.5;
}

.article-body pre code {
    background: none;
    border: none;
    padding: 0;
}

.article-body a { color: var(--accent); }
.article-body a:hover { color: var(--accent-hover); }

.article-body ul, .article-body ol {
    margin: 12px 0 20px 24px;
}

.article-body li { margin-bottom: 6px; }

.article-body blockquote {
    border-left: 3px solid var(--accent);
    padding: 8px 16px;
    margin: 20px 0;
    background: rgba(88, 166, 255, 0.05);
    border-radius: 0 var(--radius) var(--radius) 0;
    color: var(--text-muted);
}

.article-body strong { color: var(--text); }

.article-nav { margin-top: 60px; padding-top: 24px; border-top: 1px solid var(--border); }
.article-nav a { color: var(--accent); text-decoration: none; }

/* Not found */
.not-found { text-align: center; padding: 120px 20px; }
.not-found h1 { font-size: 4rem; color: var(--text-muted); margin-bottom: 16px; }
.not-found a { color: var(--accent); }

/* Footer */
.site-footer {
    margin-top: auto;
    border-top: 1px solid var(--border);
    padding: 24px 0;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.empty { color: var(--text-muted); text-align: center; padding: 40px; }

/* Responsive */
@media (max-width: 640px) {
    .hero h1 { font-size: 1.8rem; }
    .hero { padding: 50px 16px 40px; }
    .article-card { padding: 20px; }
}