:root{--primary:#1a73e8;--primary-dark:#1557b0;--text:#1f2937;--text-light:#6b7280;--bg:#fff;--bg-alt:#f9fafb;--border:#e5e7eb;--radius:8px;--shadow:0 1px 3px rgba(0,0,0,.08);--max-w:800px;--transition:150ms ease}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,sans-serif;color:var(--text);background:var(--bg);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:var(--primary);text-decoration:none;transition:color var(--transition)}
a:hover{color:var(--primary-dark)}
img{max-width:100%;height:auto;display:block;border-radius:var(--radius)}

/* Layout */
.container{max-width:var(--max-w);margin:0 auto;padding:0 1.25rem}
.wide{--max-w:1100px}

/* Header */
.site-header{background:var(--bg);border-bottom:1px solid var(--border);padding:1rem 0;position:sticky;top:0;z-index:10;backdrop-filter:blur(8px);background:rgba(255,255,255,.92)}
.site-header .container{display:flex;align-items:center;justify-content:space-between}
.logo{font-size:1.25rem;font-weight:700;color:var(--text)}
.logo span{color:var(--primary)}
.site-nav{display:flex;gap:1.5rem;list-style:none}
.site-nav a{color:var(--text-light);font-size:.9rem;font-weight:500}
.site-nav a:hover{color:var(--primary)}

/* Hero */
.hero{padding:3rem 0 2rem;text-align:center}
.hero h1{font-size:clamp(1.75rem,4vw,2.5rem);line-height:1.2;margin-bottom:1rem}
.hero p{color:var(--text-light);font-size:1.1rem;max-width:600px;margin:0 auto}

/* Cards grid */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:1.5rem;padding:2rem 0 3rem}
.card{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;transition:box-shadow var(--transition),transform var(--transition)}
.card:hover{box-shadow:0 4px 12px rgba(0,0,0,.1);transform:translateY(-2px)}
.card-img{width:100%;aspect-ratio:16/9;object-fit:cover;background:var(--bg-alt)}
.card-body{padding:1.25rem}
.card-body h2{font-size:1.1rem;margin-bottom:.5rem;line-height:1.3}
.card-body p{color:var(--text-light);font-size:.9rem;line-height:1.6}
.card-link{display:inline-block;margin-top:.75rem;font-size:.85rem;font-weight:600}

/* Article */
.article-header{padding:2.5rem 0 1.5rem;text-align:center}
.article-header h1{font-size:clamp(1.5rem,3.5vw,2.25rem);line-height:1.25;margin-bottom:.75rem}
.article-meta{color:var(--text-light);font-size:.85rem;display:flex;gap:1rem;justify-content:center;flex-wrap:wrap}
.article-hero{margin:1rem 0 2rem;border-radius:var(--radius);overflow:hidden}
.article-hero img{width:100%;aspect-ratio:2/1;object-fit:cover}
.article-content{padding-bottom:3rem}
.article-content h2{font-size:1.4rem;margin:2rem 0 .75rem;color:var(--text);border-left:3px solid var(--primary);padding-left:.75rem}
.article-content h3{font-size:1.15rem;margin:1.5rem 0 .5rem}
.article-content p{margin-bottom:1rem;color:#374151}
.article-content ul,.article-content ol{margin:1rem 0 1rem 1.5rem;color:#374151}
.article-content li{margin-bottom:.4rem}
.article-content blockquote{border-left:3px solid var(--primary);padding:.75rem 1rem;background:var(--bg-alt);margin:1.5rem 0;border-radius:0 var(--radius) var(--radius) 0;color:var(--text-light);font-style:italic}
.article-content .info-box{background:#eff6ff;border:1px solid #bfdbfe;border-radius:var(--radius);padding:1rem 1.25rem;margin:1.5rem 0}
.article-content .info-box strong{color:var(--primary)}
.article-content .warning-box{background:#fef3c7;border:1px solid #fde68a;border-radius:var(--radius);padding:1rem 1.25rem;margin:1.5rem 0}
.article-content table{width:100%;border-collapse:collapse;margin:1.5rem 0;font-size:.9rem}
.article-content th,.article-content td{padding:.6rem .75rem;border:1px solid var(--border);text-align:left}
.article-content th{background:var(--bg-alt);font-weight:600}

/* TOC */
.toc{background:var(--bg-alt);border:1px solid var(--border);border-radius:var(--radius);padding:1.25rem 1.5rem;margin:0 0 2rem}
.toc-title{font-weight:700;margin-bottom:.5rem;font-size:.95rem}
.toc ol{margin:0;padding-left:1.25rem}
.toc li{margin-bottom:.3rem;font-size:.9rem}
.toc a{color:var(--text-light)}
.toc a:hover{color:var(--primary)}

/* Breadcrumb */
.breadcrumb{padding:.75rem 0;font-size:.8rem;color:var(--text-light)}
.breadcrumb a{color:var(--text-light)}
.breadcrumb span{margin:0 .4rem}

/* Footer */
.site-footer{background:var(--bg-alt);border-top:1px solid var(--border);padding:2rem 0;text-align:center;color:var(--text-light);font-size:.85rem}
.site-footer a{color:var(--text-light)}

/* FAQ Schema */
.faq{margin:2rem 0}
.faq-item{border:1px solid var(--border);border-radius:var(--radius);margin-bottom:.75rem;overflow:hidden}
.faq-q{padding:.85rem 1rem;font-weight:600;cursor:pointer;background:var(--bg-alt);display:flex;justify-content:space-between;align-items:center;font-size:.95rem}
.faq-q::after{content:"+";font-size:1.2rem;color:var(--text-light);transition:transform var(--transition)}
.faq-item.open .faq-q::after{transform:rotate(45deg)}
.faq-a{padding:0 1rem;max-height:0;overflow:hidden;transition:max-height .3s ease,padding .3s ease;font-size:.9rem;color:#374151}
.faq-item.open .faq-a{padding:.75rem 1rem;max-height:500px}

/* Related */
.related{padding:2rem 0 1rem;border-top:1px solid var(--border);margin-top:2rem}
.related h2{font-size:1.2rem;margin-bottom:1rem;border:0;padding:0}
.related-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem}

@media(max-width:640px){
  .cards{grid-template-columns:1fr}
  .site-nav{gap:.75rem}
  .site-nav a{font-size:.8rem}
  .related-grid{grid-template-columns:1fr}
}