/* Look of the /learn pages (dm/Learn). Colours match the lesson visuals (scripts/fmri_visuals/style.py):
   the site's navy and teal, and the same categorical palette, so a page and its post look like one thing.
   learn.js sets <html data-theme="light|dark"> when the reader picks one; with no choice the system setting wins. */
:root {
  --surface: #FFFFFF;
  --panel: #F8FAFC;
  --border: #E2E8F0;
  --ink: #0F172A;
  --muted: #475569;
  --primary: #0F4C81;
  --accent: #0F766E;
  --s1: #2a78d6; --s2: #eb6834; --s3: #1baf7a; --s4: #eda100; --s5: #e87ba4; --s6: #008300;
  --noise: #e34948;
  --oxy: #c8323a;
  --deoxy: #3150c4;
  --focus: #2a78d6;
  --shadow: 0 1px 2px rgba(15, 23, 42, .06), 0 4px 16px rgba(15, 23, 42, .06);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --surface: #0B1F3A; --panel: #11294A; --border: #1E3A5F; --ink: #E2E8F0; --muted: #94A3B8;
    --primary: #7CB9F0; --accent: #2DD4BF;
    --s1: #3987e5; --s2: #d95926; --s3: #199e70; --s4: #c98500; --s5: #d55181; --s6: #008300;
    --noise: #e66767; --oxy: #f2706b; --deoxy: #8aa2ff; --focus: #7CB9F0;
    --shadow: none;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --surface: #0B1F3A; --panel: #11294A; --border: #1E3A5F; --ink: #E2E8F0; --muted: #94A3B8;
  --primary: #7CB9F0; --accent: #2DD4BF;
  --s1: #3987e5; --s2: #d95926; --s3: #199e70; --s4: #c98500; --s5: #d55181; --s6: #008300;
  --noise: #e66767; --oxy: #f2706b; --deoxy: #8aa2ff; --focus: #7CB9F0;
  --shadow: none;
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; }
body {
  background: var(--surface);
  color: var(--ink);
  font: 16px/1.6 "Segoe UI", system-ui, -apple-system, Roboto, sans-serif;
  overflow-x: hidden;
}
a { color: var(--primary); }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 4px; }

/* ---- Frame ---- */
.lt-top, .lt-main, .lt-foot { max-width: 1040px; margin: 0 auto; padding-left: 16px; padding-right: 16px; }
.lt-top { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding-top: 14px; flex-wrap: wrap; }
.lt-crumbs { display: flex; gap: 8px; flex-wrap: wrap; font-size: .9rem; color: var(--muted); }
.lt-crumbs a { color: var(--muted); text-decoration: none; }
.lt-crumbs a:hover { color: var(--ink); text-decoration: underline; }
.lt-theme { font: inherit; font-size: .85rem; padding: 6px 14px; border-radius: 99px; cursor: pointer;
            border: 1px solid var(--border); background: var(--panel); color: var(--ink); }
.lt-theme::before { content: "◐ "; }
.lt-main { padding-top: 8px; padding-bottom: 32px; }
.lt-foot { border-top: 1px solid var(--border); padding-top: 12px; padding-bottom: 32px; color: var(--muted); font-size: .85rem; }
h1 { font-size: clamp(1.6rem, 4vw, 2.1rem); line-height: 1.2; margin: 20px 0 6px; }
h2 { font-size: 1.15rem; margin: 0 0 10px; }
.lt-lede { color: var(--muted); max-width: 680px; margin: 0 0 20px; }
.lt-small { color: var(--muted); font-size: .85rem; }

/* ---- Cards (index and hub) ---- */
.lt-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.lt-card { display: flex; flex-direction: column; gap: 6px; padding: 18px; border-radius: 14px; text-decoration: none;
           background: var(--panel); border: 1px solid var(--border); color: var(--ink); box-shadow: var(--shadow);
           transition: transform .15s, border-color .15s; }
a.lt-card:hover, a.lt-card:focus-visible { transform: translateY(-2px); border-color: var(--primary); }
.lt-icon { font-size: 1.8rem; line-height: 1; }
.lt-name { font-weight: 700; font-size: 1.05rem; }
.lt-what { color: var(--muted); font-size: .92rem; flex: 1; }
.lt-meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; font-size: .8rem; color: var(--muted); margin-top: 6px; }
.lt-meta > :last-child { margin-left: auto; }
.lt-tag { padding: 1px 10px; border-radius: 99px; border: 1px solid var(--border); }
.lt-go { color: var(--primary); font-weight: 600; }
.lt-soon { opacity: .6; }
.lt-soon .lt-tag:last-child { border-style: dashed; }

/* ---- Page sections ---- */
.lt-stage { background: var(--panel); border: 1px solid var(--border); border-radius: 14px; padding: 16px; margin-bottom: 16px; box-shadow: var(--shadow); }
.lt-panel { padding: 16px 0; border-top: 1px solid var(--border); }
.lt-terms { display: grid; grid-template-columns: max-content 1fr; gap: 6px 16px; margin: 0; }
.lt-terms dt { font-weight: 600; }
.lt-terms dd { margin: 0; color: var(--muted); }
@media (max-width: 560px) { .lt-terms { grid-template-columns: 1fr; } .lt-terms dd { margin-bottom: 8px; } }
.lt-sources { margin: 0; padding-left: 20px; }
.lt-pager { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding: 16px 0; border-top: 1px solid var(--border); font-size: .92rem; }

/* ---- Interactive parts ---- */
.lt-figure { position: relative; width: 100%; }
.lt-figure canvas, .lt-figure svg, .lt-stage canvas { display: block; width: 100%; height: auto; }
.lt-controls { display: flex; flex-wrap: wrap; gap: 10px 16px; align-items: center; margin: 12px 0 4px; }
.lt-btn { font: inherit; font-size: .92rem; padding: 7px 14px; border-radius: 8px; cursor: pointer;
          border: 1px solid var(--border); background: var(--surface); color: var(--ink); min-height: 40px; }
.lt-btn:hover { border-color: var(--primary); }
.lt-btn[aria-pressed="true"], .lt-btn.lt-primary { background: var(--primary); border-color: var(--primary); color: var(--surface); }
.lt-control { display: inline-flex; align-items: center; gap: 8px; font-size: .92rem; }
.lt-control input[type="range"] { width: min(220px, 50vw); accent-color: var(--primary); }
.lt-control select { font: inherit; padding: 6px 8px; border-radius: 8px; border: 1px solid var(--border); background: var(--surface); color: var(--ink); }
.lt-readout { font-variant-numeric: tabular-nums; font-weight: 600; }
.lt-legend { display: flex; flex-wrap: wrap; gap: 6px 16px; font-size: .85rem; color: var(--muted); margin: 6px 0; }
.lt-swatch { display: inline-block; width: 12px; height: 12px; border-radius: 3px; margin-right: 6px; vertical-align: -1px; }
.lt-label-synthetic::after, .lt-label-schematic::after { font-size: .75rem; color: var(--muted); border: 1px dashed var(--border);
  border-radius: 99px; padding: 0 8px; margin-left: 8px; }
.lt-label-synthetic::after { content: "synthetic data"; }
.lt-label-schematic::after { content: "schematic, not to scale"; }

.lt-two { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 12px; }
@media (max-width: 720px) { .lt-two { grid-template-columns: 1fr; } }
.lt-chart-title { font-size: .9rem; font-weight: 600; margin: 0 0 4px; }
.lt-chart-note { font-size: .8rem; color: var(--muted); margin: 2px 0 0; }
.lt-status { font-size: .92rem; min-height: 1.6em; margin: 8px 0 0; }
.lt-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; margin-top: 12px; }
.lt-mini { border: 1px solid var(--border); border-radius: 12px; padding: 12px 14px; background: var(--surface); }
.lt-mini h3 { font-size: 1rem; margin: 0 0 6px; }
.lt-mini p, .lt-mini ul { margin: 4px 0; font-size: .9rem; }
.lt-mini ul { padding-left: 18px; }
.lt-chain { display: flex; flex-wrap: wrap; gap: 6px; align-items: stretch; margin: 12px 0 4px; padding: 0; list-style: none; }
.lt-chain li { flex: 1 1 140px; border: 2px solid var(--border); border-radius: 10px; padding: 8px 10px; font-size: .88rem;
               background: var(--surface); transition: border-color .3s, background .3s; }
.lt-chain li strong { display: block; font-size: .92rem; }
.lt-chain li.on { border-color: var(--accent); }
.lt-chain li .lt-arrow { color: var(--muted); }
.lt-note-exaggerated { font-size: .8rem; color: var(--muted); font-style: italic; }

/* Callout shown by Learn.callout() on hover, focus or tap */
.lt-callout { position: absolute; z-index: 10; max-width: min(320px, calc(100vw - 32px)); padding: 10px 12px; border-radius: 10px;
              background: var(--surface); color: var(--ink); border: 1px solid var(--border); font-size: .88rem; line-height: 1.45;
              box-shadow: 0 6px 24px rgba(0, 0, 0, .18); pointer-events: none; }
.lt-callout[hidden] { display: none; }
.lt-callout strong { display: block; margin-bottom: 2px; }
[data-callout] { cursor: pointer; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}