:root{
  --ink:#162033;
  --muted:#5f6c7c;
  --line:#dde3ea;
  --soft:#f5f7f9;
  --paper:#ffffff;
  --accent:#204f7a;
  --accent-soft:#eaf2f8;
  --max:1120px;
  --reading:780px;
  font-family:Inter,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  color:var(--ink);
  background:#fbfcfd;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:#fbfcfd;color:var(--ink)}
a{color:var(--accent)}
img{max-width:100%;height:auto}
.site-shell{max-width:var(--max);margin:0 auto;padding:0 28px}
.site-header{border-bottom:1px solid var(--line);background:rgba(251,252,253,.96)}
.site-header-inner{max-width:var(--max);margin:0 auto;padding:18px 28px;display:flex;align-items:center;gap:28px}
.site-brand{font-weight:800;text-decoration:none;color:var(--ink);letter-spacing:-.02em;white-space:nowrap}
.site-nav{display:flex;gap:18px;flex-wrap:wrap;font-size:.94rem}
.site-nav a{color:#465365;text-decoration:none}
.site-nav a:hover,.site-nav a[aria-current="page"]{color:var(--ink);text-decoration:underline;text-underline-offset:5px}
.site-spacer{flex:1}
.learn-link{font-size:.9rem;text-decoration:none;border:1px solid var(--line);padding:8px 12px;border-radius:8px;color:var(--ink)}
.hero{padding:82px 0 54px}
.hero-kicker,.eyebrow{font-size:.82rem;text-transform:uppercase;letter-spacing:.08em;font-weight:800;color:#667487}
.hero h1{font-size:clamp(2.55rem,7vw,5.35rem);line-height:.98;letter-spacing:-.055em;max-width:900px;margin:10px 0 22px}
.hero p{font-size:1.18rem;line-height:1.65;color:var(--muted);max-width:760px;margin:0}
.section{padding:34px 0 52px}
.section h2{font-size:1.9rem;letter-spacing:-.025em;margin:0 0 16px}
.section-intro{max-width:760px;color:var(--muted);line-height:1.65;margin:0 0 28px}
.subject-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1px;background:var(--line);border:1px solid var(--line)}
.subject-card{background:var(--paper);padding:24px;text-decoration:none;color:var(--ink);min-height:170px}
.subject-card:hover{background:#f9fbfc}
.subject-card small{display:block;text-transform:uppercase;letter-spacing:.06em;color:#718094;font-weight:700;margin-bottom:24px}
.subject-card h3{font-size:1.2rem;margin:0 0 8px}
.subject-card p{margin:0;color:var(--muted);line-height:1.55}
.feature-list{display:grid;gap:0;border-top:1px solid var(--line)}
.feature-row{display:grid;grid-template-columns:180px 1fr;gap:26px;padding:24px 0;border-bottom:1px solid var(--line);text-decoration:none;color:var(--ink)}
.feature-meta{font-size:.82rem;text-transform:uppercase;letter-spacing:.05em;color:#718094;font-weight:700}
.feature-row h3{margin:0 0 7px;font-size:1.25rem}
.feature-row p{margin:0;color:var(--muted);line-height:1.55}
.page-head{padding:58px 0 30px}
.page-head h1{font-size:clamp(2.2rem,6vw,4.5rem);letter-spacing:-.045em;line-height:1;margin:8px 0 14px}
.page-head p{max-width:760px;color:var(--muted);font-size:1.12rem;line-height:1.65}
.content-grid{display:grid;grid-template-columns:2fr 1fr;gap:52px;align-items:start}
.prose{max-width:var(--reading);font-family:Georgia,"Times New Roman",serif;font-size:1.13rem;line-height:1.8}
.prose h2,.prose h3{font-family:Inter,system-ui,sans-serif;letter-spacing:-.02em}
.prose h2{font-size:1.5rem;margin-top:42px}
.prose h3{font-size:1.12rem;margin-top:30px}
.prose p{margin:0 0 22px}
.callout{font-family:Inter,system-ui,sans-serif;border-left:3px solid var(--accent);background:var(--accent-soft);padding:18px 20px;margin:30px 0}
.callout strong{display:block;margin-bottom:6px}
.practice{font-family:Inter,system-ui,sans-serif;border-top:1px solid var(--line);margin-top:34px;padding-top:24px}
.practice ol,.practice ul{padding-left:22px}
.practice li{margin:12px 0;line-height:1.55}
.term-list{font-family:Inter,system-ui,sans-serif;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:28px 0}
.term{border:1px solid var(--line);background:var(--paper);padding:16px}
.term strong{display:block;margin-bottom:6px}
.sidebar{font-size:.94rem;line-height:1.55}
.sidebar-box{border-top:3px solid var(--ink);padding-top:14px;margin-bottom:30px}
.sidebar-box h2,.sidebar-box h3{font-size:1rem;margin:0 0 10px}
.sidebar-box p,.sidebar-box li{color:var(--muted)}
.article-shell{max-width:var(--reading);margin:0 auto;padding:0 26px}
.breadcrumb{font-size:.9rem;color:#6c7888;margin:24px 0 42px}
.breadcrumb a{color:#526174}
.article-title{font-family:Inter,system-ui,sans-serif;font-size:clamp(2.45rem,7vw,4.7rem);line-height:1.01;letter-spacing:-.045em;margin:8px 0 18px}
.article-dek{font-family:Georgia,"Times New Roman",serif;font-size:1.24rem;line-height:1.55;color:#526074;margin-bottom:18px}
.article-meta{font-size:.9rem;color:#6f7c8d;margin:20px 0 36px}
.article-body{font-family:Georgia,"Times New Roman",serif;font-size:1.16rem;line-height:1.8}
.article-body h2{font-family:Inter,system-ui,sans-serif;font-size:1.42rem;letter-spacing:-.02em;margin-top:40px}
.article-body p{margin:0 0 22px}
.article-box{font-family:Inter,system-ui,sans-serif;border-top:1px solid var(--line);padding:26px 0;margin-top:28px}
.article-box h2{margin:0 0 14px;font-size:1.25rem}
.article-box.private{border:1px solid #24344a;background:#172033;color:white;padding:22px}
.article-box.private a{color:white}
.site-footer{margin-top:70px;border-top:1px solid var(--line);padding:30px 0 45px;color:#748092;font-size:.88rem}
.site-footer-inner{max-width:var(--max);margin:0 auto;padding:0 28px;display:flex;gap:24px;justify-content:space-between;flex-wrap:wrap}
.footer-links{display:flex;gap:16px;flex-wrap:wrap}
.footer-links a{color:#667487;text-decoration:none}
@media(max-width:820px){
  .site-header-inner{align-items:flex-start;flex-wrap:wrap}
  .site-nav{order:3;width:100%}
  .site-spacer{display:none}
  .subject-grid{grid-template-columns:1fr}
  .feature-row{grid-template-columns:1fr;gap:8px}
  .content-grid{grid-template-columns:1fr}
  .term-list{grid-template-columns:1fr}
  .hero{padding-top:58px}
}