/* Agent Evals: Zero to Expert — shared styles
   Theme: "sky lab notebook". Airy blue-white paper, deep navy ink, one clear blue accent,
   semantic hues (green/amber/red/violet) reserved for meaning. Dark mode = navy night version. */
@import url("https://fonts.googleapis.com/css2?family=Sora:wght@500;600;700;800&family=IBM+Plex+Sans:ital,wght@0,400;0,500;0,600;0,700;1,400&family=JetBrains+Mono:wght@400;600&display=swap");
:root {
  --bg: #f4f8fd;
  --bg-2: #e8f1fc;
  --surface: #ffffff;
  --surface-2: #eaf2fc;
  --text: #0e2340;
  --muted: #52647d;
  --line: #d3e1f2;
  --ink: #3c5575;
  --accent: #1f6fd6;
  --accent-2: #38a8f0;
  --accent-soft: #e2eefc;
  --good: #13865a;
  --good-soft: #dcf4ea;
  --bad: #d0453b;
  --bad-soft: #fde6e3;
  --warn: #b8730a;
  --warn-soft: #fdf0d6;
  --violet: #6d4fd8;
  --violet-soft: #ece7fd;
  --code-bg: #f1f6fd;
  --shadow: 0 1px 2px rgba(14, 35, 64, .05), 0 10px 30px -14px rgba(31, 111, 214, .28);
  --radius: 14px;
  --maxw: 880px;
  --display: "Sora", "Segoe UI", system-ui, sans-serif;
  --font: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --bg: #0b1524; --bg-2: #0f1d33; --surface: #111e33; --surface-2: #172842; --text: #e6eefa; --muted: #9db0cc;
  --line: #26395a; --ink: #a9bddb; --accent: #6fb2ff; --accent-2: #5fd0ff; --accent-soft: #16304f;
  --good: #56d39a; --good-soft: #123526; --bad: #ff8a80; --bad-soft: #3f1f24; --warn: #f5b95a; --warn-soft: #3a2d17;
  --violet: #b39cff; --violet-soft: #2a2450; --code-bg: #0f1b2e;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 12px 30px -16px rgba(0, 0, 0, .6);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--text); font-family: var(--font);
  font-size: 17px; line-height: 1.65; -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }

/* ---------- layout ---------- */
.topbar {
  position: sticky; top: 0; z-index: 20; display: flex; align-items: center; gap: 12px;
  padding: 10px 16px; background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px); border-bottom: 1px solid var(--line);
}
.topbar .brand { font-weight: 700; color: var(--text); text-decoration: none; letter-spacing: -0.01em; }
.topbar .brand span { color: var(--accent); }
.topbar .spacer { flex: 1; }
.iconbtn {
  border: 1px solid var(--line); background: var(--surface); color: var(--text); border-radius: 8px;
  padding: 6px 10px; font: inherit; font-size: 14px; cursor: pointer;
}
.progressbar { position: absolute; left: 0; bottom: -1px; height: 2px; background: var(--accent); width: 0; }

.shell { display: grid; grid-template-columns: 280px minmax(0, 1fr); max-width: 1280px; margin: 0 auto; }
.sidebar {
  position: sticky; top: 53px; height: calc(100vh - 53px); overflow-y: auto; padding: 20px 12px 40px 16px;
  border-right: 1px solid var(--line); font-size: 14px;
}
.sidebar h4 { margin: 18px 8px 6px; font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); }
.sidebar a { display: flex; gap: 8px; padding: 5px 8px; border-radius: 6px; color: var(--text); text-decoration: none; line-height: 1.35; }
.sidebar a .n { color: var(--muted); font-variant-numeric: tabular-nums; min-width: 1.6em; }
.sidebar a:hover { background: var(--surface-2); }
.sidebar a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.sidebar a.done .n::after { content: " ✓"; color: var(--good); }

main { padding: 32px 16px 80px; min-width: 0; }
.content { max-width: var(--maxw); margin: 0 auto; }
@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }
  .sidebar { display: none; position: fixed; inset: 53px 0 0 0; height: auto; background: var(--bg); z-index: 15; border: 0; }
  body.nav-open .sidebar { display: block; }
  body { font-size: 16px; }
}
@media (min-width: 901px) { .navtoggle { display: none; } }

/* ---------- typography ---------- */
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.015em; }
h1 { font-size: clamp(30px, 5vw, 42px); margin: 8px 0 12px; }
h2 { font-size: 26px; margin: 56px 0 12px; padding-top: 8px; border-top: 1px solid var(--line); }
h3 { font-size: 20px; margin: 32px 0 8px; }
.kicker { font-size: 13px; text-transform: uppercase; letter-spacing: .1em; color: var(--accent); font-weight: 700; }
.lede { font-size: 19px; color: var(--muted); margin-top: 0; }
p, ul, ol { margin: 0 0 16px; }
li { margin-bottom: 6px; }
code { font-family: var(--mono); font-size: .88em; background: var(--code-bg); padding: 1px 5px; border-radius: 4px; }
pre { background: var(--code-bg); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; overflow-x: auto; font-size: 14px; line-height: 1.55; position: relative; }
pre code { background: none; padding: 0; font-size: inherit; }
pre .copy { position: absolute; top: 6px; right: 6px; font-size: 12px; opacity: .7; }
pre[data-lang]::before { content: attr(data-lang); position: absolute; top: 6px; right: 60px; font-size: 11px; color: var(--muted); font-family: var(--font); }
.tok-c { color: var(--muted); font-style: italic; }
.tok-k { color: var(--violet); }
.tok-s { color: var(--good); }
kbd { font-family: var(--mono); font-size: .85em; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 4px; padding: 0 4px; }
hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }

/* ---------- components ---------- */
.meta { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0 24px; }
.pill { font-size: 13px; padding: 3px 10px; border-radius: 999px; background: var(--surface-2); color: var(--muted); border: 1px solid var(--line); }
.pill.level-1 { background: var(--good-soft); color: var(--good); border-color: transparent; }
.pill.level-2 { background: var(--accent-soft); color: var(--accent); border-color: transparent; }
.pill.level-3 { background: var(--warn-soft); color: var(--warn); border-color: transparent; }
.pill.level-4 { background: var(--violet-soft); color: var(--violet); border-color: transparent; }

.callout { border: 1px solid var(--line); border-left: 4px solid var(--accent); background: var(--surface); border-radius: var(--radius); padding: 14px 16px; margin: 20px 0; }
.callout > :last-child { margin-bottom: 0; }
.callout .t { font-weight: 700; display: block; margin-bottom: 4px; }
.callout.tip { border-left-color: var(--good); }
.callout.warn { border-left-color: var(--warn); }
.callout.bad { border-left-color: var(--bad); }
.callout.expert { border-left-color: var(--violet); background: color-mix(in srgb, var(--violet-soft) 40%, var(--surface)); }
.callout.analogy { border-left-color: var(--warn); background: color-mix(in srgb, var(--warn-soft) 35%, var(--surface)); }

.objectives { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 20px; }
.objectives h3 { margin-top: 0; font-size: 16px; }
.objectives ul { margin-bottom: 0; }

.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 14px; margin: 18px 0; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; }
.card h4 { margin: 0 0 6px; font-size: 16px; }
.card p:last-child, .card ul:last-child { margin-bottom: 0; }
.card.good { border-top: 3px solid var(--good); }
.card.bad { border-top: 3px solid var(--bad); }
.card.accent { border-top: 3px solid var(--accent); }
.card.warn { border-top: 3px solid var(--warn); }
.card.violet { border-top: 3px solid var(--violet); }

.tablewrap { overflow-x: auto; margin: 18px 0; border: 1px solid var(--line); border-radius: var(--radius); }
table { border-collapse: collapse; width: 100%; font-size: 14.5px; background: var(--surface); }
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: var(--surface-2); font-weight: 600; white-space: nowrap; }
tr:last-child td { border-bottom: 0; }
td .y { color: var(--good); font-weight: 700; } td .n { color: var(--bad); font-weight: 700; } td .p { color: var(--warn); font-weight: 700; }

details { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 10px 14px; margin: 10px 0; }
details summary { cursor: pointer; font-weight: 600; }
details[open] summary { margin-bottom: 8px; }

.quiz { margin: 24px 0; }
.quiz .q { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; margin-bottom: 12px; }
.quiz .q p { font-weight: 600; }
.quiz button.opt { display: block; width: 100%; text-align: left; margin: 6px 0; padding: 8px 12px; border-radius: 8px; border: 1px solid var(--line); background: var(--bg); color: var(--text); font: inherit; font-size: 15px; cursor: pointer; }
.quiz button.opt.right { border-color: var(--good); background: var(--good-soft); }
.quiz button.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.quiz .why { display: none; font-size: 15px; color: var(--muted); margin-top: 8px; }
.quiz .q.answered .why { display: block; }

.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 60px; flex-wrap: wrap; }
.pager a { flex: 1 1 240px; border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 16px; text-decoration: none; background: var(--surface); }
.pager a small { display: block; color: var(--muted); }
.pager a.next { text-align: right; }

.sources { font-size: 14px; color: var(--muted); }
.sources li { margin-bottom: 4px; word-break: break-word; }
.toc { font-size: 15px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 18px; margin: 20px 0; }
.toc ol { margin: 6px 0 0; padding-left: 20px; }

/* ---------- diagrams ---------- */
figure.diagram { margin: 26px 0; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; }
figure.diagram svg { display: block; width: 100%; height: auto; max-width: 100%; color: var(--text); font-family: var(--font); }
figure.diagram figcaption { font-size: 14px; color: var(--muted); margin-top: 10px; border-top: 1px dashed var(--line); padding-top: 8px; }
figure.diagram figcaption b { color: var(--text); }
.diagram svg text { fill: currentColor; font-size: 13px; }
.diagram svg text.sm { font-size: 11px; fill: var(--muted); }
.diagram svg text.lg { font-size: 15px; font-weight: 700; }
.diagram svg text.b { font-weight: 700; }
.diagram svg text.mono { font-family: var(--mono); font-size: 11.5px; }
.diagram svg .box { fill: var(--surface-2); stroke: currentColor; stroke-width: 1.2; }
.diagram svg .box.plain { fill: var(--surface); }
.diagram svg .box.accent { fill: var(--accent-soft); stroke: var(--accent); }
.diagram svg .box.good { fill: var(--good-soft); stroke: var(--good); }
.diagram svg .box.bad { fill: var(--bad-soft); stroke: var(--bad); }
.diagram svg .box.warn { fill: var(--warn-soft); stroke: var(--warn); }
.diagram svg .box.violet { fill: var(--violet-soft); stroke: var(--violet); }
.diagram svg .box.dashed { stroke-dasharray: 5 4; fill: none; }
.diagram svg .ln { stroke: currentColor; stroke-width: 1.4; fill: none; }
.diagram svg .ln.dash { stroke-dasharray: 5 4; }
.diagram svg .ln.accent { stroke: var(--accent); }
.diagram svg .ln.good { stroke: var(--good); }
.diagram svg .ln.bad { stroke: var(--bad); }
.diagram svg .ln.warn { stroke: var(--warn); }
.diagram svg .ln.violet { stroke: var(--violet); }
.diagram svg .ln.thick { stroke-width: 2.4; }
.diagram svg .fill-accent { fill: var(--accent); } .diagram svg .fill-good { fill: var(--good); }
.diagram svg .fill-bad { fill: var(--bad); } .diagram svg .fill-warn { fill: var(--warn); }
.diagram svg .fill-violet { fill: var(--violet); } .diagram svg .fill-muted { fill: var(--muted); }
.diagram svg .fill-line { fill: var(--line); } .diagram svg .fill-soft { fill: var(--surface-2); }
.diagram svg text.t-accent { fill: var(--accent); } .diagram svg text.t-good { fill: var(--good); }
.diagram svg text.t-bad { fill: var(--bad); } .diagram svg text.t-warn { fill: var(--warn); }
.diagram svg text.t-violet { fill: var(--violet); } .diagram svg text.t-muted { fill: var(--muted); }
.diagram svg marker path { fill: currentColor; }

/* ---------- home ---------- */
.hero { padding: 24px 0 8px; }
.hero h1 { font-size: clamp(34px, 6vw, 54px); }
.partgrid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.partgrid .card a { text-decoration: none; }
.partgrid .card ol { padding-left: 22px; margin: 8px 0 0; font-size: 15px; }
.btn { display: inline-block; background: var(--accent); color: #fff; border-radius: 8px; padding: 10px 18px; text-decoration: none; font-weight: 600; }
:root[data-theme="dark"] .btn { color: #0d1220; }

/* ---------- motion ---------- */
@keyframes aez-dash { to { stroke-dashoffset: -24; } }
@keyframes aez-pulse { 0%,100% { opacity: 1; } 50% { opacity: .45; } }
.diagram svg .ln.flow { stroke-dasharray: 6 6; animation: aez-dash 1.1s linear infinite; }
.diagram svg .pulse { animation: aez-pulse 2.2s ease-in-out infinite; }
figure.diagram, .card, .callout { transition: opacity .6s ease, transform .6s ease; }
.reveal-pending { opacity: 0; transform: translateY(14px); }
@media (prefers-reduced-motion: reduce) {
  .diagram svg .ln.flow, .diagram svg .pulse { animation: none; }
  .reveal-pending { opacity: 1; transform: none; }
  html { scroll-behavior: auto; }
}
/* animate arrows in the diagram currently on screen */
figure.diagram.in-view svg line.ln[marker-end]:not(.dash), figure.diagram.in-view svg path.ln[marker-end]:not(.dash) { stroke-dasharray: 7 5; animation: aez-dash 1.4s linear infinite; }
@media (prefers-reduced-motion: reduce) { figure.diagram.in-view svg .ln { animation: none !important; stroke-dasharray: none; } }

/* ---------- interactive widgets ---------- */
.widget { background: var(--surface); border: 1px solid var(--line); border-top: 3px solid var(--accent); border-radius: var(--radius); padding: 16px; margin: 26px 0; }
.widget h4 { margin: 0 0 4px; font-size: 16px; display: flex; gap: 8px; align-items: center; }
.widget h4::before { content: "▶ Try it"; font-size: 11px; letter-spacing: .08em; text-transform: uppercase; background: var(--accent); color: var(--bg); border-radius: 4px; padding: 2px 6px; }
.widget .wdesc { font-size: 14px; color: var(--muted); margin-bottom: 12px; }
.widget .controls { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 10px 18px; margin-bottom: 12px; }
.widget label { font-size: 14px; display: flex; flex-direction: column; gap: 4px; }
.widget label b { font-variant-numeric: tabular-nums; color: var(--accent); }
.widget input[type=range] { width: 100%; accent-color: var(--accent); }
.widget input[type=text], .widget textarea { width: 100%; font: inherit; font-size: 14px; padding: 6px 8px; border-radius: 6px; border: 1px solid var(--line); background: var(--bg); color: var(--text); }
.widget .readout { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 10px; }
.widget .stat { background: var(--surface-2); border-radius: 8px; padding: 8px 12px; min-width: 120px; }
.widget .stat small { display: block; font-size: 12px; color: var(--muted); }
.widget .stat span { font-size: 20px; font-weight: 700; font-variant-numeric: tabular-nums; }
.widget svg { width: 100%; height: auto; display: block; color: var(--text); font-family: var(--font); }
.widget svg text { fill: currentColor; font-size: 12px; }
.widget .note { font-size: 13px; color: var(--muted); margin-top: 8px; }
.widget button.run { font: inherit; font-size: 14px; border-radius: 8px; border: 0; background: var(--accent); color: var(--bg); padding: 6px 14px; cursor: pointer; }

/* ---------- 3D hero ---------- */
.hero3d { position: relative; height: 340px; margin: 8px 0 18px; border-radius: 14px; overflow: hidden; border: 1px solid var(--line);
  background: radial-gradient(120% 90% at 50% 10%, var(--accent-soft), var(--surface) 70%); }
.hero3d canvas { display: block; width: 100% !important; height: 100% !important; }
.hero3d .legend3d { position: absolute; left: 12px; bottom: 10px; font-size: 12px; color: var(--muted); background: color-mix(in srgb, var(--surface) 80%, transparent); padding: 4px 8px; border-radius: 6px; }
.hero3d .fallback { position: absolute; inset: 0; display: grid; place-items: center; color: var(--muted); font-size: 14px; }
@media (max-width: 600px) { .hero3d { height: 240px; } }
p code, li code, td code { overflow-wrap: anywhere; }

/* =====================================================================
   Sky theme layer (overrides earlier rules)
   ===================================================================== */
body {
  font-family: var(--font);
  background:
    radial-gradient(1200px 520px at 85% -120px, color-mix(in srgb, var(--accent-2) 16%, transparent), transparent 70%),
    radial-gradient(900px 420px at -10% 10%, color-mix(in srgb, var(--accent) 8%, transparent), transparent 70%),
    var(--bg);
  background-attachment: fixed;
}
h1, h2, h3, h4, .brand, .kicker, .pill, .sidebar h4 { font-family: var(--display); }
h1, h2, h3 { text-wrap: balance; color: var(--text); }
h1 { font-weight: 800; letter-spacing: -0.03em;
  background: linear-gradient(100deg, var(--text) 30%, var(--accent) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent; }
h2 { font-weight: 700; border-top: 0; padding-top: 0; margin-top: 64px; position: relative; }
h2::before { content: ""; display: block; width: 44px; height: 4px; border-radius: 4px; margin-bottom: 14px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2)); }
h3 { font-weight: 600; }
.lede { color: var(--ink); }
strong, b { color: inherit; }
.kicker { display: inline-block; font-size: 12px; letter-spacing: .12em; padding: 5px 12px; border-radius: 999px;
  background: var(--accent-soft); color: var(--accent); }

/* top bar + sidebar */
.topbar { background: color-mix(in srgb, var(--surface) 82%, transparent); border-bottom: 1px solid var(--line);
  box-shadow: 0 1px 0 color-mix(in srgb, var(--accent) 10%, transparent); }
.topbar .brand { font-weight: 800; }
.topbar .brand span { background: linear-gradient(90deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.progressbar { height: 3px; background: linear-gradient(90deg, var(--accent), var(--accent-2)); border-radius: 0 3px 3px 0; }
.iconbtn { border-radius: 10px; transition: background .2s, border-color .2s; }
.iconbtn:hover { border-color: var(--accent); background: var(--accent-soft); }
.iconbtn:focus-visible, a:focus-visible, button:focus-visible, summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.sidebar { background: color-mix(in srgb, var(--surface) 55%, transparent); }
.sidebar a { border-radius: 8px; transition: background .15s; }
.sidebar a.active { background: linear-gradient(90deg, var(--accent-soft), transparent); color: var(--accent);
  box-shadow: inset 3px 0 0 var(--accent); }

/* surfaces */
.card, .objectives, .toc, details, .quiz .q, .pager a, .widget, .tablewrap { box-shadow: var(--shadow); border-color: var(--line); }
.card { border-radius: var(--radius); transition: transform .2s ease, box-shadow .2s ease; }
.card:hover { transform: translateY(-2px); }
.card.good { border-top-width: 4px; } .card.bad { border-top-width: 4px; } .card.accent { border-top-width: 4px; }
.card.warn { border-top-width: 4px; } .card.violet { border-top-width: 4px; }
.objectives { background: linear-gradient(135deg, var(--surface), var(--accent-soft)); border-radius: var(--radius); }
.toc { border-radius: var(--radius); }
.toc ol { columns: 2 240px; column-gap: 28px; }
.pill { font-family: var(--font); font-weight: 600; }

.callout { border-radius: var(--radius); border: 1px solid var(--line); border-left-width: 5px; box-shadow: var(--shadow);
  background: color-mix(in srgb, var(--accent-soft) 45%, var(--surface)); }
.callout.tip { background: color-mix(in srgb, var(--good-soft) 55%, var(--surface)); }
.callout.warn { background: color-mix(in srgb, var(--warn-soft) 55%, var(--surface)); }
.callout.bad { background: color-mix(in srgb, var(--bad-soft) 55%, var(--surface)); }
.callout.expert { background: color-mix(in srgb, var(--violet-soft) 55%, var(--surface)); }
.callout .t { font-family: var(--display); font-size: 15px; }

.tablewrap { border-radius: var(--radius); }
th { background: var(--surface-2); color: var(--text); font-family: var(--display); font-size: 13.5px; }
tr:nth-child(even) td { background: color-mix(in srgb, var(--surface-2) 35%, var(--surface)); }
tr:hover td { background: color-mix(in srgb, var(--accent-soft) 70%, var(--surface)); }

pre { background: var(--code-bg); border-radius: 12px; border-color: var(--line); box-shadow: inset 0 1px 0 color-mix(in srgb, var(--surface) 60%, transparent); }
code { background: var(--accent-soft); color: color-mix(in srgb, var(--text) 85%, var(--accent)); }
pre code { color: var(--text); }
/* syntax colors (highlight.js classes), themed by tokens */
.hljs-comment, .hljs-quote { color: var(--muted); font-style: italic; }
.hljs-keyword, .hljs-selector-tag, .hljs-literal, .hljs-built_in { color: var(--violet); }
.hljs-string, .hljs-regexp, .hljs-addition { color: var(--good); }
.hljs-number, .hljs-symbol, .hljs-bullet { color: var(--warn); }
.hljs-title, .hljs-title.function_, .hljs-section { color: var(--accent); font-weight: 600; }
.hljs-attr, .hljs-attribute, .hljs-variable, .hljs-template-variable, .hljs-property { color: color-mix(in srgb, var(--accent) 70%, var(--text)); }
.hljs-meta, .hljs-params { color: var(--ink); }
.hljs-deletion { color: var(--bad); }

/* diagrams: blueprint paper */
figure.diagram { border-radius: 18px; box-shadow: var(--shadow); border-color: var(--line);
  background-color: var(--surface);
  background-image: radial-gradient(color-mix(in srgb, var(--accent) 16%, transparent) 1px, transparent 1.2px);
  background-size: 18px 18px; background-position: 9px 9px; }
figure.diagram figcaption { background: color-mix(in srgb, var(--surface) 92%, transparent); border-radius: 10px; padding: 10px 12px; border-top: 0;
  margin: 12px -4px -4px; box-shadow: inset 0 0 0 1px var(--line); }
.diagram svg .box { fill: var(--surface); stroke: color-mix(in srgb, var(--ink) 70%, var(--surface)); stroke-width: 1.3;
  filter: drop-shadow(0 1px 1.5px rgba(14, 35, 64, .10)); }
.diagram svg .box.plain { fill: var(--surface); }
.diagram svg .box.dashed { fill: none; filter: none; stroke: color-mix(in srgb, var(--ink) 60%, var(--surface)); }
.diagram svg .ln { stroke: color-mix(in srgb, var(--ink) 85%, var(--surface)); }
.diagram svg marker path { fill: color-mix(in srgb, var(--ink) 85%, var(--surface)); }
.diagram svg text { fill: var(--text); }
.diagram svg text.sm { fill: var(--muted); }
.diagram svg .fill-soft { fill: var(--surface-2); }
:root[data-theme="dark"] .diagram svg .box { filter: none; }

/* widgets */
.widget { border-radius: 18px; border-top: 0; position: relative; overflow: hidden;
  background: linear-gradient(180deg, color-mix(in srgb, var(--accent-soft) 60%, var(--surface)) 0, var(--surface) 140px); }
.widget::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 4px; background: linear-gradient(90deg, var(--accent), var(--accent-2)); }
.widget h4 { font-family: var(--display); }
.widget h4::before { background: linear-gradient(90deg, var(--accent), var(--accent-2)); color: #fff; }
.widget .stat { background: var(--surface); box-shadow: inset 0 0 0 1px var(--line); border-radius: 12px; }
.widget .stat span { font-family: var(--display); color: var(--accent); }
.widget input[type=range] { height: 6px; }

/* quiz */
.quiz button.opt { border-radius: 10px; transition: border-color .15s, background .15s, transform .1s; }
.quiz button.opt:hover { border-color: var(--accent); background: var(--accent-soft); }
.quiz button.opt:active { transform: scale(.99); }

/* buttons + pager */
.btn { background: linear-gradient(95deg, var(--accent), var(--accent-2)); color: #fff; border-radius: 12px; padding: 12px 22px;
  box-shadow: 0 10px 24px -12px var(--accent); transition: transform .15s, box-shadow .15s; }
.btn:hover { transform: translateY(-1px); box-shadow: 0 14px 28px -12px var(--accent); }
:root[data-theme="dark"] .btn { color: #07111f; }
.pager a { border-radius: var(--radius); transition: border-color .2s, transform .2s; }
.pager a:hover { border-color: var(--accent); transform: translateY(-2px); }

/* module hero band */
.content > .kicker:first-child { margin-top: 6px; }
.modnum { float: right; font-family: var(--display); font-weight: 800; font-size: clamp(64px, 12vw, 120px); line-height: .8;
  margin: -6px 0 0 16px; color: transparent; -webkit-text-stroke: 2px color-mix(in srgb, var(--accent) 35%, transparent);
  user-select: none; pointer-events: none; }
@media (max-width: 600px) { .modnum { display: none; } }

/* key takeaways */
.takeaways { border-radius: 18px; padding: 18px 20px; margin: 30px 0; color: var(--text); box-shadow: var(--shadow);
  background: linear-gradient(135deg, var(--accent-soft), color-mix(in srgb, var(--violet-soft) 60%, var(--surface))); border: 1px solid var(--line); }
.takeaways h3 { margin-top: 0; font-size: 18px; }
.takeaways ol { margin: 0; padding-left: 22px; }

/* home */
.hero h1 { font-size: clamp(38px, 7vw, 64px); }
.hero3d { border-radius: 22px; box-shadow: var(--shadow);
  background: radial-gradient(120% 90% at 50% 0%, color-mix(in srgb, var(--accent-2) 22%, var(--surface)), var(--surface) 72%); }
.stats { display: flex; flex-wrap: wrap; gap: 12px; margin: 18px 0 8px; }
.stats div { flex: 1 1 130px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 12px 14px; box-shadow: var(--shadow); }
.stats b { display: block; font-family: var(--display); font-size: 28px; color: var(--accent); line-height: 1.1; }
.stats span { font-size: 13px; color: var(--muted); }

/* diagram zoom */
figure.diagram { position: relative; }
.zoombtn { position: absolute; top: 10px; right: 10px; font-size: 12px; padding: 4px 9px; opacity: 0; transition: opacity .2s; }
figure.diagram:hover .zoombtn, .zoombtn:focus-visible { opacity: 1; }
@media (hover: none) { .zoombtn { opacity: .85; } }
.lightbox { position: fixed; inset: 0; z-index: 100; background: color-mix(in srgb, var(--bg) 92%, transparent); backdrop-filter: blur(6px);
  display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 56px 16px 20px; gap: 12px; }
.lightbox[hidden] { display: none; }
.lightbox .lbinner { width: min(1500px, 100%); max-height: 78vh; overflow: auto; background: var(--surface); border-radius: 18px; padding: 18px; box-shadow: var(--shadow); color: var(--text); }
.lightbox .lbinner svg { width: 100%; height: auto; display: block; font-family: var(--font); }
.lightbox .lbinner svg text { fill: var(--text); font-size: 13px; }
.lightbox .lbinner svg text.sm { fill: var(--muted); font-size: 11px; }
.lightbox .lbcap { max-width: 900px; font-size: 14px; color: var(--muted); text-align: center; }
.lightbox .lbclose { position: absolute; top: 14px; right: 16px; }

/* color classes win over the muted default for small text, inline and in the lightbox */
.diagram svg text.t-accent, .diagram svg text.sm.t-accent { fill: var(--accent); }
.diagram svg text.t-good, .diagram svg text.sm.t-good { fill: var(--good); }
.diagram svg text.t-bad, .diagram svg text.sm.t-bad { fill: var(--bad); }
.diagram svg text.t-warn, .diagram svg text.sm.t-warn { fill: var(--warn); }
.diagram svg text.t-violet, .diagram svg text.sm.t-violet { fill: var(--violet); }
.lightbox .lbinner svg text.t-accent { fill: var(--accent); }
.lightbox .lbinner svg text.t-good { fill: var(--good); }
.lightbox .lbinner svg text.t-bad { fill: var(--bad); }
.lightbox .lbinner svg text.t-warn { fill: var(--warn); }
.lightbox .lbinner svg text.t-violet { fill: var(--violet); }