:root {
  --bg: #0b0d10;
  --panel: #12161b;
  --panel-2: #181d23;
  --text: #eef2f6;
  --muted: #9ba7b4;
  --line: #2a313a;
  --accent: #79a8ff;
  --accent-2: #b7c9ff;
  --good: #8fd6af;
  --shadow: 0 20px 60px rgba(0,0,0,.22);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: radial-gradient(circle at top, #111824 0, var(--bg) 36rem); color: var(--text); line-height: 1.65; }
a { color: inherit; text-decoration: none; }
a:hover { color: var(--accent-2); }
.site-header { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; justify-content: space-between; gap: 2rem; padding: 1rem clamp(1rem, 4vw, 4rem); border-bottom: 1px solid rgba(255,255,255,.08); background: rgba(11,13,16,.88); backdrop-filter: blur(14px); }
.brand { font-size: 1.15rem; font-weight: 760; letter-spacing: .08em; }
nav { display: flex; gap: .35rem; flex-wrap: wrap; }
nav a { padding: .45rem .8rem; border-radius: 999px; color: var(--muted); }
nav a.active, nav a:hover { color: var(--text); background: rgba(255,255,255,.06); }
main { width: min(1180px, calc(100% - 2rem)); margin: 0 auto; }
.hero { min-height: 72vh; display: grid; align-content: center; max-width: 900px; padding: 7rem 0 5rem; }
.eyebrow { color: var(--accent); font-size: .74rem; letter-spacing: .18em; text-transform: uppercase; font-weight: 760; }
h1, h2, h3 { line-height: 1.18; letter-spacing: -.025em; }
.hero h1 { margin: .8rem 0 1.4rem; font-size: clamp(2.5rem, 7vw, 5.8rem); max-width: 1000px; }
.hero p, .page-head p { color: var(--muted); font-size: clamp(1rem, 2vw, 1.25rem); max-width: 760px; }
.hero-actions { display: flex; gap: .8rem; margin-top: 1.5rem; flex-wrap: wrap; }
.button { display: inline-flex; align-items: center; justify-content: center; padding: .78rem 1rem; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); font-weight: 680; }
.button.primary { background: var(--text); color: var(--bg); border-color: var(--text); }
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin: 0 0 5rem; }
.feature-grid.two { grid-template-columns: repeat(2, 1fr); }
.feature-grid article, .content-card, .detail-card, .network-card, .course-browser { background: linear-gradient(180deg, rgba(255,255,255,.035), rgba(255,255,255,.012)); border: 1px solid var(--line); border-radius: 18px; padding: 1.25rem; box-shadow: var(--shadow); }
.feature-grid p, .feature-grid li, .content-card p { color: var(--muted); }
.number { color: var(--accent); font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: .82rem; }
.callout { margin: 3rem 0 5rem; border: 1px solid var(--line); border-radius: 22px; padding: clamp(1.4rem, 4vw, 2.4rem); display: flex; align-items: end; justify-content: space-between; gap: 2rem; background: linear-gradient(120deg, rgba(121,168,255,.12), rgba(255,255,255,.02)); }
.callout p { color: var(--muted); max-width: 780px; }
.callout > a { color: var(--accent-2); white-space: nowrap; }
.page-head { padding: 5.5rem 0 2.5rem; }
.page-head.compact { padding-bottom: 1.5rem; }
.page-head h1 { font-size: clamp(2.4rem, 6vw, 4.8rem); margin: .6rem 0 1rem; }
footer { width: min(1180px, calc(100% - 2rem)); margin: 4rem auto 0; padding: 2rem 0 3rem; border-top: 1px solid var(--line); color: var(--muted); font-size: .9rem; }
.graph-toolbar, .library-toolbar { display: flex; gap: .9rem; align-items: end; flex-wrap: wrap; margin-bottom: 1rem; padding: 1rem; background: rgba(18,22,27,.7); border: 1px solid var(--line); border-radius: 16px; }
.graph-toolbar label { display: grid; gap: .35rem; min-width: 240px; font-size: .78rem; color: var(--muted); }
input, select, button { font: inherit; }
input, select { color: var(--text); background: var(--panel-2); border: 1px solid var(--line); border-radius: 10px; padding: .72rem .8rem; outline: none; }
input:focus, select:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(121,168,255,.12); }
.muted { color: var(--muted); }
.graph-layout { display: grid; grid-template-columns: minmax(220px, .8fr) minmax(420px, 1.7fr) minmax(260px, 1fr); gap: 1rem; align-items: start; }
.course-browser { padding: .5rem; max-height: 620px; overflow: auto; }
.course-results { display: grid; gap: .35rem; }
.course-item { width: 100%; display: grid; gap: .15rem; text-align: left; padding: .68rem .72rem; border: 0; border-radius: 10px; background: transparent; color: var(--text); cursor: pointer; }
.course-item:hover, .course-item.active { background: rgba(121,168,255,.11); }
.course-item small { color: var(--muted); }
.network-card { padding: .7rem; }
#network { width: 100%; min-height: 520px; display: block; background: radial-gradient(circle, rgba(255,255,255,.04), transparent 60%); border-radius: 12px; }
.network-help { color: var(--muted); font-size: .8rem; margin: .3rem .5rem .15rem; }
.net-edge { stroke: #536170; stroke-width: 1.5; opacity: .65; }
.net-edge.incoming { stroke: #7fa7ef; }
.net-node { cursor: pointer; }
.net-node circle { fill: #1e2732; stroke: #6f7c8a; stroke-width: 1.5; }
.net-node.focus circle { fill: #79a8ff; stroke: #dce7ff; }
.net-node text { fill: #dfe6ee; font-size: 12px; pointer-events: none; paint-order: stroke; stroke: #0b0d10; stroke-width: 4px; stroke-linejoin: round; }
.detail-card { min-height: 250px; }
.detail-card h2 { margin-top: .25rem; }
.detail-row { margin: .9rem 0; }
.detail-row strong { display: block; margin-bottom: .35rem; font-size: .78rem; color: var(--muted); text-transform: uppercase; letter-spacing: .08em; }
.link-list { display: flex; flex-wrap: wrap; gap: .4rem; }
.pill, .tag { display: inline-flex; border: 1px solid var(--line); border-radius: 999px; padding: .25rem .55rem; font-size: .78rem; color: var(--muted); background: rgba(255,255,255,.025); }
.pill.clickable { cursor: pointer; color: var(--text); }
.pill.clickable:hover { border-color: var(--accent); }
.empty-state { color: var(--muted); }
.library-toolbar > input { flex: 1 1 360px; }
.segmented { display: flex; gap: .25rem; }
.segmented button { border: 1px solid var(--line); background: var(--panel-2); color: var(--muted); border-radius: 9px; padding: .62rem .8rem; cursor: pointer; }
.segmented button.active { color: var(--bg); background: var(--text); border-color: var(--text); }
.tag-cloud { display: flex; gap: .4rem; flex-wrap: wrap; margin: 1rem 0; }
.tag-cloud button { border: 1px solid var(--line); border-radius: 999px; padding: .28rem .6rem; background: transparent; color: var(--muted); cursor: pointer; }
.tag-cloud button.active { color: var(--text); border-color: var(--accent); background: rgba(121,168,255,.08); }
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.content-card h3 { margin: .45rem 0 .5rem; font-size: 1.2rem; }
.content-card .tags { display: flex; flex-wrap: wrap; gap: .3rem; }
.article { width: min(820px, 100%); margin: 0 auto; padding: 5rem 0; }
.article h1 { font-size: clamp(2.3rem, 6vw, 4rem); margin: .6rem 0 1rem; }
.lead { color: var(--muted); font-size: 1.15rem; }
.prose p, .prose li { color: #cbd4dd; }
.prose h2, .prose h3 { margin-top: 2.3rem; }
.prose pre { overflow: auto; padding: 1rem; border: 1px solid var(--line); background: #080a0d; border-radius: 12px; }
.prose code { font-family: ui-monospace, SFMono-Regular, Consolas, monospace; background: rgba(255,255,255,.06); padding: .1rem .28rem; border-radius: 5px; }
.prose blockquote { border-left: 3px solid var(--accent); margin: 1.5rem 0; padding: .4rem 1rem; color: var(--muted); background: rgba(121,168,255,.05); }
.tags { display: flex; gap: .35rem; flex-wrap: wrap; margin: .9rem 0; }
.course-links { margin: 1rem 0 2rem; padding: .85rem 1rem; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); }
.course-links a { color: var(--accent-2); margin-left: .5rem; }
.narrow { max-width: 780px; margin: 3rem 0 5rem; }
.error-box { border: 1px solid #6c3f4a; background: #24171b; color: #f0cbd2; padding: 1rem; border-radius: 12px; }
@media (max-width: 1050px) { .graph-layout { grid-template-columns: 1fr 1.6fr; } .detail-card { grid-column: 1 / -1; } .card-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 760px) { .site-header { align-items: flex-start; flex-direction: column; gap: .5rem; } .hero { min-height: auto; padding-top: 4rem; } .feature-grid, .feature-grid.two, .card-grid, .graph-layout { grid-template-columns: 1fr; } .network-card { order: 3; } .detail-card { grid-column: auto; } #network { min-height: 420px; } .callout { align-items: flex-start; flex-direction: column; } }
@media (prefers-color-scheme: light) {
  :root { --bg:#f5f7fa; --panel:#ffffff; --panel-2:#f2f5f8; --text:#111820; --muted:#5d6975; --line:#d7dee6; --accent:#285fb7; --accent-2:#174a9c; --shadow:0 18px 50px rgba(35,45,55,.08); }
  body { background: radial-gradient(circle at top,#eef4ff 0,var(--bg) 36rem); }
  .site-header { background: rgba(245,247,250,.9); border-color: rgba(0,0,0,.08); }
  .net-node text { fill:#17212b; stroke:#f7f9fb; }
  .prose p, .prose li { color:#2c3742; }
  .prose pre { background:#eef2f6; }
}