@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Inter:wght@400;500&display=swap');

:root {
  --color-primary: #1e40af;
  --color-secondary: #6b7280;
  --color-bg: #ffffff;
  --color-text: #111827;
  --color-accent: #2563eb;
  --color-border: #e5e7eb;
  --color-surface: #f9fafb;
  --font-heading: 'DM Sans', sans-serif;
  --font-body: 'Inter', sans-serif;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: var(--font-body); color: var(--color-text); background: var(--color-bg); line-height: 1.7; font-size: 17px; -webkit-font-smoothing: antialiased; }
a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }

.container { max-width: 740px; margin: 0 auto; padding: 0 1.5rem; }
.container-wide { max-width: 1120px; margin: 0 auto; padding: 0 1.5rem; }

.site-header { position: sticky; top: 0; z-index: 100; background: var(--color-bg); box-shadow: 0 1px 3px rgba(0,0,0,0.06); padding: 0.875rem 0; }
.site-header .container-wide { display: flex; align-items: center; justify-content: space-between; }
.site-header .brand { font-family: var(--font-heading); font-weight: 700; font-size: 1.35rem; color: var(--color-text); letter-spacing: -0.02em; }
.site-header .brand:hover { text-decoration: none; }
.site-header nav { display: flex; align-items: center; gap: 1.75rem; }
.site-header nav a { color: var(--color-secondary); font-size: 0.9rem; font-weight: 500; transition: color 0.15s; }
.site-header nav a:hover { color: var(--color-text); text-decoration: none; }

.hero { padding: 4rem 0 3rem; border-bottom: 1px solid var(--color-border); }
.hero h1 { font-family: var(--font-heading); font-size: 2.5rem; font-weight: 700; letter-spacing: -0.03em; line-height: 1.15; margin-bottom: 0.75rem; }
.hero p { font-size: 1.15rem; color: var(--color-secondary); max-width: 560px; }

.section-title { font-family: var(--font-heading); font-size: 1.35rem; font-weight: 600; letter-spacing: -0.01em; margin-bottom: 1.5rem; padding-top: 2.5rem; }

.article-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 1.75rem; }

.article-card { border: 1px solid var(--color-border); border-radius: 12px; overflow: hidden; transition: box-shadow 0.2s, transform 0.2s; background: var(--color-bg); }
.article-card:hover { box-shadow: 0 8px 24px rgba(0,0,0,0.08); transform: translateY(-2px); }
.article-card a { color: inherit; text-decoration: none; display: block; }
.article-card a:hover { text-decoration: none; }
.card-img { width: 100%; height: 200px; object-fit: cover; background: linear-gradient(135deg, var(--color-surface) 0%, #e5e7eb 100%); }
.card-body { padding: 1.25rem 1.5rem 1.5rem; }
.card-category { display: inline-block; font-size: 0.75rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; color: var(--color-accent); margin-bottom: 0.5rem; }
.card-body h3 { font-family: var(--font-heading); font-size: 1.1rem; font-weight: 600; line-height: 1.35; margin-bottom: 0.5rem; letter-spacing: -0.01em; color: var(--color-text); }
.card-excerpt { font-size: 0.9rem; color: var(--color-secondary); line-height: 1.55; margin-bottom: 0.75rem; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.card-meta { font-size: 0.8rem; color: #9ca3af; display: flex; align-items: center; gap: 0.5rem; }
.card-meta .dot { width: 3px; height: 3px; border-radius: 50%; background: #d1d5db; display: inline-block; }

.featured-card { grid-column: 1 / -1; display: grid; grid-template-columns: 1.2fr 1fr; border: 1px solid var(--color-border); border-radius: 12px; overflow: hidden; transition: box-shadow 0.2s; }
.featured-card:hover { box-shadow: 0 8px 24px rgba(0,0,0,0.08); }
.featured-card a { color: inherit; text-decoration: none; display: contents; }
.featured-card a:hover { text-decoration: none; }
.featured-card .card-img { height: 100%; min-height: 280px; }
.featured-card .card-body { padding: 2rem; display: flex; flex-direction: column; justify-content: center; }
.featured-card h3 { font-size: 1.5rem; font-family: var(--font-heading); margin-bottom: 0.75rem; letter-spacing: -0.02em; color: var(--color-text); }
.featured-card .card-excerpt { -webkit-line-clamp: 3; }

article { padding: 2.5rem 0 3rem; }
article h1 { font-family: var(--font-heading); font-size: 2.25rem; font-weight: 700; letter-spacing: -0.03em; line-height: 1.2; margin-bottom: 1rem; }
article h2 { font-family: var(--font-heading); font-size: 1.45rem; font-weight: 600; letter-spacing: -0.01em; margin: 2.25rem 0 0.75rem; }
article h3 { font-family: var(--font-heading); font-size: 1.15rem; font-weight: 600; margin: 1.75rem 0 0.5rem; }
article p { margin-bottom: 1.1rem; }
article ul, article ol { margin: 0.5rem 0 1.1rem 1.5rem; }
article li { margin-bottom: 0.35rem; }
article figure { margin: 2rem 0; }
article figure img { border-radius: 10px; }
article figcaption { font-size: 0.85rem; color: var(--color-secondary); margin-top: 0.5rem; text-align: center; }

.article-meta { display: flex; align-items: center; gap: 0.75rem; color: var(--color-secondary); font-size: 0.9rem; margin-bottom: 2rem; padding-bottom: 1.25rem; border-bottom: 1px solid var(--color-border); }
.article-meta .author-name { font-weight: 500; color: var(--color-text); }
.article-meta .sep { color: #d1d5db; }

.breadcrumb { font-size: 0.85rem; color: var(--color-secondary); margin-bottom: 1.25rem; }
.breadcrumb a { color: var(--color-secondary); }
.breadcrumb a:hover { color: var(--color-accent); }
.breadcrumb .sep { margin: 0 0.4rem; color: #d1d5db; }

table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.95rem; }
th, td { padding: 0.75rem 1rem; border: 1px solid var(--color-border); text-align: left; }
th { background: var(--color-surface); font-weight: 600; font-size: 0.9rem; }
tr:hover td { background: #fafbfc; }

.callout { background: #eff6ff; border-left: 4px solid var(--color-accent); padding: 1.15rem 1.35rem; margin: 1.5rem 0; border-radius: 0 10px 10px 0; font-size: 0.95rem; }
.callout strong { display: block; margin-bottom: 0.25rem; }

details.faq-item { border: 1px solid var(--color-border); border-radius: 10px; margin: 0.65rem 0; transition: box-shadow 0.15s; }
details.faq-item:hover { box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
details.faq-item summary { padding: 1rem 1.25rem; cursor: pointer; font-weight: 500; font-size: 1rem; list-style: none; display: flex; align-items: center; justify-content: space-between; }
details.faq-item summary::after { content: '+'; font-size: 1.25rem; color: var(--color-secondary); font-weight: 300; }
details[open].faq-item summary::after { content: '\2212'; }
details.faq-item p { padding: 0 1.25rem 1.15rem; color: var(--color-secondary); }

.related-link { font-size: 0.9rem; color: var(--color-secondary); background: var(--color-surface); padding: 0.75rem 1rem; border-radius: 8px; margin: 0.75rem 0; }
.related-link a { font-weight: 500; }

.site-footer { border-top: 1px solid var(--color-border); padding: 3rem 0 2rem; margin-top: 4rem; font-size: 0.88rem; color: var(--color-secondary); background: var(--color-surface); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 2.5rem; }
.footer-grid h4 { font-family: var(--font-heading); font-weight: 600; color: var(--color-text); margin-bottom: 0.75rem; font-size: 0.95rem; }
.footer-grid p { line-height: 1.6; }
.footer-grid ul { list-style: none; }
.footer-grid li { margin-bottom: 0.4rem; }
.footer-grid a { color: var(--color-secondary); }
.footer-grid a:hover { color: var(--color-accent); }
.footer-bottom { margin-top: 2rem; padding-top: 1.5rem; border-top: 1px solid var(--color-border); text-align: center; font-size: 0.82rem; }

@media (max-width: 768px) {
  .hero h1 { font-size: 1.75rem; }
  .article-grid { grid-template-columns: 1fr; }
  .featured-card { grid-template-columns: 1fr; }
  .featured-card .card-img { min-height: 200px; }
  .footer-grid { grid-template-columns: 1fr; gap: 1.5rem; }
  article h1 { font-size: 1.65rem; }
}