/* Default theme – minimal, fast, CWV-friendly */
:root{
  --bg:#ffffff;
  --text:#1f2937;
  --muted:#6b7280;
  --card:#f8fafc;
  --border:#e5e7eb;
  --link:#2563eb;
  --accent:#111827;
  --radius:14px;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family: system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.65;
}
a{color:var(--link);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:920px;margin:0 auto;padding:24px 16px}
.site-header{border-bottom:1px solid var(--border);background:#fff}
.header-row{display:flex;align-items:baseline;justify-content:space-between;gap:12px;flex-wrap:wrap}
.brand{font-weight:800;font-size:18px;letter-spacing:.2px}
.tagline{color:var(--muted);font-size:14px;margin-top:4px}
.site-nav{display:flex;flex-wrap:wrap;gap:10px 12px;margin-top:10px}
.nav-item{font-size:14px;color:var(--text);padding:6px 10px;border:1px solid var(--border);border-radius:999px;background:#fff}
.nav-item:hover{text-decoration:none;border-color:#cbd5e1}
.nav-item.is-active{border-color:#94a3b8;box-shadow:0 0 0 2px rgba(148,163,184,.25) inset}
.sub-nav{display:flex;flex-wrap:wrap;gap:8px 10px;margin-top:10px}
.sub-nav-item{font-size:13px;color:var(--muted);padding:6px 10px;border:1px dashed var(--border);border-radius:999px;background:transparent}
.sub-nav-item.is-disabled{pointer-events:none;opacity:.85}
.sub-nav-item.is-active{border-style:solid;color:var(--text);opacity:1}
h1{font-size:34px;line-height:1.15;margin:22px 0 12px}
h2{font-size:20px;margin:0 0 10px}
.intro{font-size:16px;color:#374151;max-width:80ch}
.card{
  margin:20px 0;
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:16px;
}
.grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(210px,1fr));
  gap:12px;
}
.tile{
  display:block;
  padding:12px;
  border-radius:12px;
  border:1px solid var(--border);
  background:#fff;
}
.tile-title{font-weight:700}
.tile-url{color:var(--muted);font-size:13px;margin-top:2px}
.muted{color:var(--muted)}
.crumbs{margin:10px 0 18px;color:var(--muted);font-size:14px}
.sep{margin:0 8px;color:var(--muted)}
.content p{max-width:80ch}
.content ul{padding-left:20px}
.site-footer{border-top:1px solid var(--border);margin-top:34px}
.footer-grid{display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}

/* Category hub: left sidebar */
.page-grid{
  display:grid;
  grid-template-columns:240px 1fr;
  gap:16px;
  align-items:start;
}
.sidebar{position:relative}
.sidebar-title{font-weight:800;color:var(--text);margin:10px 0 10px;font-size:13px;text-transform:uppercase;letter-spacing:.06em}
.sidebar-nav ul{list-style:none;margin:0;padding:0}
.sidebar-nav li{margin:6px 0}
.sidebar-nav a,
.sidebar-nav .is-disabled{
  display:block;
  padding:8px 10px;
  border:1px solid var(--border);
  border-radius:12px;
  background:#fff;
  color:var(--text);
  font-size:14px;
}
.sidebar-nav a:hover{text-decoration:none;border-color:#cbd5e1}
.sidebar-nav li.is-active a{border-color:#94a3b8;box-shadow:0 0 0 2px rgba(148,163,184,.25) inset}
.sidebar-nav .is-disabled{opacity:.65;border-style:dashed}

@media (max-width: 860px){
  .page-grid{grid-template-columns:1fr}
  .sidebar{order:2}
  .page-main{order:1}
}