:root {
  --ink: #1c1f2a;
  --muted: #586074;
  --line: #e1e3ea;
  --soft: #f5f5f9;
  --paper: #ffffff;
  --accent: #5b3f99;
  --accent-ink: #47307c;
  --accent-soft: #eee9f8;
  --hero: #17151f;
  --hero-ink: #f5f2fb;
  --hero-muted: #c8c2d6;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font: 16px/1.7 var(--sans);
  -webkit-font-smoothing: antialiased;
}
img, video { display: block; max-width: 100%; height: auto; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible, select:focus-visible, summary:focus-visible {
  outline: 3px solid #9b82d6;
  outline-offset: 3px;
}
h1, h2, h3, p, figure { margin: 0; }
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.02em; text-wrap: balance; }
h2 { font-size: clamp(26px, 3vw, 34px); font-weight: 700; }
h3 { font-size: 18px; font-weight: 650; }
sup { font-size: 0.68em; line-height: 0; }

.skip { position: fixed; top: -60px; left: 12px; z-index: 50; padding: 10px 14px; background: var(--paper); border-radius: 6px; }
.skip:focus { top: 12px; }

/* Navigation */
.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 28px;
  padding: 12px max(20px, calc((100% - 1180px) / 2));
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.wordmark { font-weight: 700; font-size: 17px; letter-spacing: -0.02em; color: var(--ink); }
.wordmark:hover { text-decoration: none; color: var(--accent); }
.nav-sections { display: flex; gap: 22px; font-size: 14px; margin-right: auto; }
.nav-sections a { color: var(--muted); }
.nav-sections a:hover { color: var(--ink); text-decoration: none; }
.nav-links { display: flex; gap: 8px; margin-left: auto; }
.nav-button {
  font-size: 13px;
  font-weight: 600;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--ink);
}
.nav-button:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }

/* Hero */
.hero {
  color: var(--hero-ink);
  background:
    radial-gradient(1100px 520px at 85% 20%, rgba(111, 78, 186, 0.35), transparent 60%),
    var(--hero);
}
.hero-inner { max-width: 1180px; margin: 0 auto; padding: 64px 32px 72px; }
.hero h1 { font-size: clamp(32px, 4.2vw, 54px); font-weight: 700; letter-spacing: -0.035em; max-width: 1080px; }
.hero h1 .accent { color: #c9b6f0; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(280px, 400px); gap: 48px; margin-top: 34px; align-items: start; }
.authors, .affiliations { display: flex; flex-wrap: wrap; list-style: none; margin: 0; padding: 0; }
.authors { gap: 4px 18px; font-size: 17px; font-weight: 500; }
.authors li, .affiliations li { white-space: nowrap; }
.authors sup { margin-left: 2px; color: var(--hero-muted); }
.authors a { color: inherit; }
.authors a:hover { color: #ffffff; text-decoration: underline; text-underline-offset: 4px; }
.affiliations { gap: 2px 16px; margin-top: 14px; font-size: 14px; color: var(--hero-muted); }
.equal { margin-top: 6px; font-size: 14px; color: var(--hero-muted); }
.hero-summary { margin-top: 26px; max-width: 620px; font-size: 18px; line-height: 1.65; color: var(--hero-ink); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.button {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-height: 48px;
  padding: 10px 20px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 650;
  color: var(--hero);
  background: #ffffff;
  border: 1px solid #ffffff;
}
.button:hover { background: #ece6f8; text-decoration: none; }
.button-note { font-size: 13px; font-weight: 500; color: #6a6480; }
.button.ghost { color: var(--hero-ink); background: transparent; border-color: rgba(255, 255, 255, 0.45); }
.button.ghost:hover { background: rgba(255, 255, 255, 0.08); }
.hero-media video {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  background: #2a2733;
}
.hero-media figcaption { margin-top: 10px; font-size: 13px; color: var(--hero-muted); }
#hero-domain { color: var(--hero-ink); font-weight: 600; }

/* Sections */
.section { max-width: 1180px; margin: 0 auto; padding: 76px 32px; }
.band { background: var(--soft); border-block: 1px solid var(--line); }
.section-heading { display: grid; grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr); gap: 48px; margin-bottom: 36px; }
.lead { display: grid; gap: 14px; }
.lead p { color: var(--muted); max-width: 68ch; }
.lead em { color: var(--ink); }
.subheading { font-size: 22px; margin-top: 64px; }
.subtext { color: var(--muted); max-width: 72ch; margin-top: 10px; }

.figure { margin-top: 28px; }
.figure img { width: 100%; border: 1px solid var(--line); border-radius: 10px; background: #fff; }
.figure figcaption { margin-top: 12px; max-width: 90ch; font-size: 14px; line-height: 1.65; color: var(--muted); }
.figure figcaption strong { color: var(--ink); font-weight: 600; }

/* Videos */
.toolbar { display: flex; align-items: center; gap: 12px; margin-bottom: 22px; font-size: 14px; color: var(--muted); }
select {
  font: inherit;
  color: var(--ink);
  padding: 7px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
}
.video-grid { display: grid; gap: 22px; }
.video-card {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: 26px;
  align-items: start;
  padding: 18px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.video-card video { width: 100%; aspect-ratio: 1520 / 900; border-radius: 8px; background: #1b1a22; }
.video-text { display: grid; gap: 10px; }
.video-text h3 { font-size: 21px; }
.video-text p { color: var(--muted); font-size: 15px; }
.video-text .learned { color: var(--ink); padding-left: 12px; border-left: 3px solid var(--accent); }

/* Cards and stats */
.cards { display: grid; gap: 22px; margin-top: 34px; }
.cards.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.cards article { padding-top: 16px; border-top: 2px solid var(--accent); }
.cards h3 { margin-bottom: 8px; }
.cards p { color: var(--muted); font-size: 15px; }
.stats { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; padding: 22px 0; border-block: 1px solid var(--line); }
.stats strong { display: block; font-size: 30px; font-weight: 700; letter-spacing: -0.03em; font-variant-numeric: tabular-nums; }
.stats span { display: block; margin-top: 4px; font-size: 14px; color: var(--muted); max-width: 34ch; }

/* Code */
.code-card { border: 1px solid var(--line); border-radius: 10px; overflow: hidden; background: #fbfbfd; }
.code-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 9px 14px;
  font: 500 13px var(--mono);
  color: var(--muted);
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}
.code-note { font-family: var(--sans); font-size: 12px; color: var(--muted); }
pre.code {
  margin: 0;
  padding: 14px 16px;
  overflow-x: auto;
  font: 13px/1.6 var(--mono);
  color: #2b2f3a;
  tab-size: 4;
}
.code-full { margin-top: 18px; }
.code-full summary { cursor: pointer; font-size: 14px; font-weight: 600; color: var(--accent); width: fit-content; }
.code-full .code-card { margin-top: 12px; }
.code-full pre.code { max-height: 70vh; }
.ln { display: inline-block; width: 3.2em; padding-right: 1.2em; text-align: right; color: #a3a8b6; user-select: none; }
.gap { display: block; padding-left: 1.2em; color: #a3a8b6; user-select: none; }
.copy { font: 500 12px var(--sans); color: var(--accent); background: none; border: 1px solid var(--line); border-radius: 6px; padding: 4px 10px; cursor: pointer; }
.copy:hover { border-color: var(--accent); }
.bibtex { white-space: pre-wrap; overflow-wrap: anywhere; }

/* Pygments tokens */
.code .c, .code .c1, .code .cm, .code .ch { color: #7c8294; font-style: italic; }
.code .sd { color: #4f6b3f; }
.code .k, .code .kn, .code .kc, .code .ow, .code .kd { color: #7a3fb0; font-weight: 500; }
.code .nf, .code .fm { color: #2458a6; }
.code .nc { color: #2458a6; font-weight: 600; }
.code .nb, .code .bp { color: #8a5a1c; }
.code .s, .code .s1, .code .s2, .code .sa, .code .se, .code .si { color: #2f7a4b; }
.code .mi, .code .mf { color: #b3541e; }
.code .nd { color: #8a5a1c; }

/* Robot */
.strip { margin-top: 34px; }
.strip h3 { font-size: 19px; }
.strip p { color: var(--muted); font-size: 15px; margin-top: 6px; max-width: 80ch; }
.frames { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; margin-top: 14px; }
.frames img { width: 100%; border-radius: 8px; border: 1px solid var(--line); }

/* Footer */
.footer { border-top: 1px solid var(--line); }
.footer-inner { max-width: 1180px; margin: 0 auto; padding: 28px 32px 40px; display: flex; flex-wrap: wrap; gap: 22px; font-size: 14px; color: var(--muted); }
.footer-inner span { font-weight: 700; color: var(--ink); margin-right: auto; }

@media (max-width: 980px) {
  .nav-sections { display: none; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-media { max-width: 420px; }
  .section-heading { grid-template-columns: 1fr; gap: 16px; }
  .video-card { grid-template-columns: 1fr; gap: 16px; }
  .cards.three, .stats { grid-template-columns: 1fr; }
}
@media (max-width: 620px) {
  .hero-inner { padding: 40px 16px 48px; }
  .section { padding: 52px 16px; }
  .footer-inner { padding-inline: 16px; }
  .authors { font-size: 16px; gap: 2px 14px; }
  .frames { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .video-card { padding: 12px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}