:root{
  --bg:#ffffff;
  --text:#111827;
  --muted:#6b7280;
  --card:#f8fafc;
  --border:rgba(17,24,39,.10);
  --link:#1d4ed8;

  --content-max:74ch;
  --radius:16px;

  --font-sans: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, Arial, sans-serif;
  --font-serif: ui-serif, Georgia, Cambria, "Times New Roman", Times, serif;
}

html[data-theme="dark"]{
  --bg:#0b1220;
  --text:#e5e7eb;
  --muted:#9ca3af;
  --card:rgba(255,255,255,.04);
  --border:rgba(229,231,235,.12);
  --link:#93c5fd;
}

*{box-sizing:border-box}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:var(--font-sans);
  font-size:17px;
  line-height:1.75;
  text-rendering:optimizeLegibility;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

a{color:var(--link);text-decoration:none}
a:hover{text-decoration:underline}

.container{
  max-width:var(--content-max);
  margin:0 auto;
  padding:24px 18px;
}

/* Two-column layout (desktop) */
.layout{display:block}
.maincol{min-width:0}
.sidebar{display:none}

@media (min-width: 1040px){
  .container{max-width:1100px}
  .layout{display:grid; grid-template-columns:minmax(0, 1fr) 320px; gap:28px; align-items:start}
  .sidebar{display:block; position:sticky; top:78px; padding-top:6px}
}

.site-header{
  position:sticky;
  top:0;
  background:color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter:saturate(160%) blur(8px);
  border-bottom:1px solid var(--border);
  z-index:10;
}

.header-inner{
  max-width:1100px;
  margin:0 auto;
  padding:14px 18px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
}

.brand{
  font-weight:700;
  letter-spacing:-0.01em;
  color:var(--text);
}

.topnav{display:none; align-items:center; gap:14px}
.topnav a{color:var(--muted); font-weight:550; font-size:.95rem}
.topnav a:hover{color:var(--text); text-decoration:none}

@media (min-width: 820px){
  .topnav{display:flex}
}

.header-actions{display:flex;align-items:center;gap:10px}

.theme-toggle{
  border:1px solid var(--border);
  background:var(--card);
  color:var(--text);
  border-radius:999px;
  padding:8px 10px;
  cursor:pointer;
  line-height:1;
}

.theme-toggle:focus{outline:2px solid color-mix(in srgb, var(--link) 55%, transparent); outline-offset:2px}

.page-title{
  font-family:var(--font-serif);
  font-size:2rem;
  line-height:1.15;
  letter-spacing:-0.015em;
  margin:0 0 10px;
}

.muted{color:var(--muted)}

.lede{
  border:1px solid var(--border);
  background:var(--card);
  border-radius:var(--radius);
  padding:14px 16px;
  margin:14px 0 22px;
  color:var(--muted);
}

.content h2{
  font-family:var(--font-serif);
  margin:30px 0 10px;
  line-height:1.2;
  letter-spacing:-0.01em;
}

.content p{margin:12px 0}
.content ul{margin:10px 0 14px 1.2rem}
.content li{margin:6px 0}

.cards{
  display:grid;
  grid-template-columns:1fr;
  gap:12px;
  margin-top:18px;
}

@media (min-width: 820px){
  .cards{grid-template-columns:1fr 1fr}
}

.card{
  display:block;
  padding:14px 14px 12px;
  border:1px solid var(--border);
  border-radius:var(--radius);
  background:var(--card);
  color:var(--text);
  transition:transform .08s ease, border-color .08s ease;
}
.card:hover{
  text-decoration:none;
  transform:translateY(-1px);
  border-color:color-mix(in srgb, var(--border) 35%, var(--link));
}

.card-title{
  font-weight:650;
  letter-spacing:-0.01em;
  margin-bottom:6px;
}

.card-summary{
  color:var(--muted);
  font-size:.97rem;
  line-height:1.55;
}

.related{
  margin-top:34px;
  padding-top:18px;
  border-top:1px solid var(--border);
}

.related-title{
  font-family:var(--font-serif);
  margin:0 0 6px;
}

.site-footer{
  border-top:1px solid var(--border);
  margin-top:42px;
}

.footer-inner{padding-top:18px;padding-bottom:22px}

.footer-links{display:flex; flex-wrap:wrap; gap:12px; margin-bottom:10px}
.footer-links a{color:var(--muted); font-size:.95rem}
.footer-links a:hover{color:var(--text); text-decoration:none}

.small{font-size:.92rem}

/* Home */
.home-hero{padding:8px 0 10px}
.home-title{font-family:var(--font-serif); font-size:2.4rem; line-height:1.05; margin:0 0 10px}
.home-tagline{color:var(--muted); margin:0 0 16px}
.home-actions{display:flex; flex-wrap:wrap; gap:10px; margin:10px 0 18px}
.btn{display:inline-block; padding:10px 12px; border-radius:999px; background:var(--text); color:var(--bg); font-weight:650; letter-spacing:-0.01em}
.btn:hover{text-decoration:none; opacity:.92}
.btn-ghost{background:transparent; color:var(--text); border:1px solid var(--border)}
.home-section{margin-top:26px}
.section-title{font-family:var(--font-serif); margin:0 0 10px; letter-spacing:-0.01em}

/* Sidebar */
.sidebox{border:1px solid var(--border); background:var(--card); border-radius:var(--radius); padding:12px 12px; margin-bottom:14px}
.sidebox-title{font-weight:700; font-size:.95rem; letter-spacing:-0.01em; margin-bottom:8px}
.sidelinks{margin:0; padding-left:18px}
.sidelinks li{margin:6px 0}
.toc .toc-body{font-size:.95rem; line-height:1.55}
.toc .toc-body ul{margin:8px 0 0 18px}

/* Ads */
.adwrap{border:1px solid var(--border); background:var(--card); border-radius:var(--radius); padding:10px; margin:18px 0}
@media (min-width: 1040px){
  .sidebar .adwrap{margin:0 0 14px}
}
.adplaceholder{min-height:180px}