/* TutorMoments-Preview site — Ai2 brand treatment
   Fonts: Space Grotesk (headings; free stand-in for Ai2's PP Telegraf),
   Manrope (body), Roboto Mono (numerals). Loaded from Google Fonts in index.html. */

:root {
  --cream: #FAF2E9;
  --cream-50: rgba(250, 242, 233, 0.5);
  --dark-teal: #0A3235;
  --teal: #105257;
  --pink: #F0529C;
  --pink-tint: #FDEEF5;
  --green: #0FCB8C;
  --ink: #343434;
  --ink-soft: rgba(10, 50, 53, 0.68);
  --ink-muted: rgba(10, 50, 53, 0.48);
  --line: rgba(10, 50, 53, 0.14);
  --card: #FFFFFF;

  --font-heading: "Space Grotesk", "Manrope", Arial, sans-serif;
  --font-body: "Manrope", Arial, sans-serif;
  --font-mono: "Roboto Mono", "Courier New", monospace;

  --radius-card: 16px;
  --radius-pill: 9999px;
  --container: 1080px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-weight: 450;
  font-size: 17px;
  line-height: 1.65;
  color: var(--dark-teal);
  background: var(--cream);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: 0;
}

a { color: var(--teal); text-decoration-color: rgba(16, 82, 87, 0.35); text-underline-offset: 3px; }
a:hover { color: var(--pink); text-decoration-color: var(--pink); }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Nav ---------- */

.nav {
  border-bottom: 1px solid var(--line);
  background: var(--cream);
}
.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.nav-brand {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--dark-teal);
  text-decoration: none;
}
.nav-brand:hover { color: var(--dark-teal); }
.nav-ai2 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--pink);
  text-decoration: none;
}
.nav-ai2:hover { color: var(--teal); }

/* ---------- Hero ---------- */

.hero { padding: 88px 0 40px; text-align: center; }
.hero h1 {
  font-size: clamp(2rem, 5.2vw, 3.4rem);
  max-width: 21ch;
  margin: 0 auto;
}
.hero h1 .preview-mark { color: var(--pink); }
.hero .tagline {
  margin: 24px auto 0;
  max-width: 46ch;
  font-size: clamp(1.1rem, 2.2vw, 1.35rem);
  color: var(--ink-soft);
  font-weight: 500;
}

/* Link pills */

.links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 36px;
}
.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: var(--radius-pill);
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.98rem;
  text-decoration: none;
  border: 1.5px solid var(--dark-teal);
  color: var(--dark-teal);
  background: transparent;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.pill svg { width: 17px; height: 17px; flex: none; }
.pill:hover { background: var(--dark-teal); color: var(--cream); }
.pill-primary { background: var(--pink); border-color: var(--pink); color: #fff; }
.pill-primary:hover { background: var(--dark-teal); border-color: var(--dark-teal); color: var(--cream); }
.pill-disabled {
  border-color: var(--line);
  color: var(--ink-muted);
  cursor: default;
  pointer-events: none;
}
.pill-disabled .soon {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  background: var(--pink-tint);
  color: var(--pink);
  border-radius: var(--radius-pill);
  padding: 2px 8px;
}

/* ---------- Sections ---------- */

.section { padding: 72px 0; }
.section-head { max-width: 62ch; margin-bottom: 36px; }
.section-head h2 { font-size: clamp(1.6rem, 3.4vw, 2.3rem); margin-bottom: 14px; }
.section-head p { color: var(--ink-soft); font-size: 1.05rem; }
.section-head .kicker {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--pink);
  margin-bottom: 10px;
}

/* Explainer block that follows a table/chart within a section */
.section-explain { margin-top: 56px; }
.section-explain h2 { font-size: clamp(1.5rem, 3vw, 2rem); margin-bottom: 14px; }
.section-explain p { color: var(--ink-soft); font-size: 1.05rem; }

/* ---------- Leaderboard ---------- */

.table-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  overflow-x: auto;
}
.table-card table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
  font-size: 0.95rem;
}
.table-card th, .table-card td {
  padding: 12px 14px;
  text-align: right;
  white-space: nowrap;
}
.table-card thead tr:not(.group-row) th:not(:first-child) {
  white-space: normal;
  max-width: 110px;
}
.table-card th:first-child, .table-card td:first-child {
  text-align: left;
  padding-left: 24px;
  font-weight: 600;
}
.table-card td:last-child, .table-card th:last-child { padding-right: 24px; }
.table-card thead th {
  font-family: var(--font-heading);
  font-weight: 500;
  color: var(--ink-soft);
  font-size: 0.82rem;
  line-height: 1.3;
  border-bottom: 1px solid var(--line);
  vertical-align: bottom;
}
.table-card thead .group-row th {
  border-bottom: none;
  padding-bottom: 2px;
  padding-top: 18px;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--dark-teal);
  text-align: center;
}
.table-card thead .group-row .group-plain { border-bottom: 3px solid var(--line); }
.table-card thead .group-row .group-aware { border-bottom: 3px solid var(--pink); }
.table-card tbody td {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  border-bottom: 1px solid rgba(10, 50, 53, 0.07);
}
.table-card tbody td:first-child { font-family: var(--font-body); font-size: 0.95rem; }
.table-card tbody tr:last-child td { border-bottom: none; }
.table-card tbody tr:hover td { background: var(--cream-50); }
.table-card td.best { color: var(--pink); font-weight: 700; }
.table-divider { border-left: 1px solid var(--line); }

.table-note {
  margin-top: 16px;
  font-size: 0.9rem;
  color: var(--ink-soft);
}
.table-note strong { color: var(--dark-teal); }

/* ---------- Animation / approach ---------- */

.band-white { background: #fff; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }

.approach-grid { display: grid; gap: 40px; }

.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  counter-reset: step;
}
.step {
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  padding: 22px 22px 20px;
}
.step::before {
  counter-increment: step;
  content: "0" counter(step);
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--pink);
  border: 1px solid var(--pink);
  border-radius: var(--radius-pill);
  padding: 2px 10px;
  margin-bottom: 12px;
}
.step h3 { font-size: 1.05rem; margin-bottom: 8px; }
.step p { font-size: 0.92rem; color: var(--ink-soft); line-height: 1.55; }

.animation-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  overflow: hidden;
  background: var(--cream);
  box-shadow: 0 2px 14px rgba(10, 50, 53, 0.06);
  /* The animation is a fixed 1280x720 stage; the iframe renders at native size
     and main.js scales it to the card's width so nothing is clipped. It is
     absolutely positioned so its native size can't inflate the layout. */
  aspect-ratio: 1280 / 720;
  position: relative;
}
.animation-card iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 1280px;
  height: 720px;
  border: 0;
  transform-origin: top left;
}
.animation-caption {
  font-size: 0.88rem;
  color: var(--ink-muted);
  margin-top: 12px;
  text-align: center;
}

.prose { max-width: 68ch; }
.prose h2 { font-size: clamp(1.5rem, 3vw, 2rem); margin-bottom: 18px; }
.prose p + p { margin-top: 16px; }
.prose strong { color: var(--dark-teal); }

/* Inside the approach grid the gap provides the spacing below the kicker */
.approach-grid .section-head { margin-bottom: -8px; }

/* ---------- Charts ---------- */

.chart-block { margin-top: 56px; }
.chart-block:first-of-type { margin-top: 0; }
.chart-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  padding: 24px 20px 16px;
  position: relative;
}
.chart-card svg { display: block; width: 100%; height: auto; font-family: var(--font-body); }
.chart-title { font-size: 1.25rem; margin-bottom: 6px; }
.chart-sub { color: var(--ink-soft); font-size: 0.98rem; max-width: 72ch; margin-bottom: 20px; }

.chart-tabs { display: inline-flex; gap: 6px; margin-bottom: 18px; background: var(--cream); border-radius: var(--radius-pill); padding: 4px; border: 1px solid var(--line); }
.chart-tabs button {
  font-family: var(--font-heading);
  font-size: 0.88rem;
  font-weight: 500;
  border: 0;
  background: transparent;
  color: var(--ink-soft);
  border-radius: var(--radius-pill);
  padding: 7px 18px;
  cursor: pointer;
}
.chart-tabs button[aria-selected="true"] { background: var(--dark-teal); color: var(--cream); }

.chart-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin: 14px 4px 4px;
  font-size: 0.85rem;
  color: var(--ink-soft);
}
.chart-legend .item { display: inline-flex; align-items: center; gap: 7px; }
.chart-legend svg { width: 14px; height: 14px; }

.chart-tooltip {
  position: fixed;
  z-index: 50;
  pointer-events: none;
  background: var(--dark-teal);
  color: var(--cream);
  font-size: 0.82rem;
  line-height: 1.5;
  border-radius: 8px;
  padding: 8px 12px;
  max-width: min(420px, calc(100vw - 24px));
  width: max-content;
  opacity: 0;
  transform: translateY(4px);
  transition: opacity 0.12s ease, transform 0.12s ease;
}
.chart-tooltip.visible { opacity: 1; transform: translateY(0); }
.chart-tooltip .tt-title { font-family: var(--font-heading); font-weight: 700; font-size: 0.86rem; }
.chart-tooltip .tt-row { display: flex; justify-content: space-between; gap: 16px; }
.chart-tooltip .tt-row .val { font-family: var(--font-mono); white-space: nowrap; }

.chart-footnote { margin-top: 14px; font-size: 0.85rem; color: var(--ink-muted); }

[hidden] { display: none !important; }

/* ---------- Authors band ---------- */

.band-dark {
  background: var(--dark-teal);
  color: var(--cream);
}
.band-dark .section-head .kicker { color: var(--green); }
.band-dark h2 { color: #fff; }
.band-dark a { color: var(--cream); text-decoration-color: rgba(250, 242, 233, 0.4); }
.band-dark a:hover { color: var(--green); }

.authors { font-size: 1.06rem; line-height: 2; max-width: 60rem; }
.authors .author { white-space: nowrap; font-weight: 600; color: #fff; }
.authors sup { font-size: 0.68em; color: var(--green); margin-left: 1px; }

.affiliations {
  margin-top: 18px;
  font-size: 0.92rem;
  color: rgba(250, 242, 233, 0.75);
  line-height: 1.9;
}
.affiliations sup { color: var(--green); margin-right: 3px; }
.affiliations span { margin-right: 18px; white-space: nowrap; }

.acknowledgments {
  margin-top: 40px;
  padding-top: 32px;
  border-top: 1px solid rgba(250, 242, 233, 0.18);
  font-size: 0.95rem;
  color: rgba(250, 242, 233, 0.75);
  max-width: 78ch;
}
.acknowledgments h3 { color: #fff; font-size: 1.1rem; margin-bottom: 12px; }

/* ---------- Footer ---------- */

.footer {
  background: var(--dark-teal);
  border-top: 1px solid rgba(250, 242, 233, 0.14);
  padding: 28px 0;
  color: rgba(250, 242, 233, 0.6);
  font-size: 0.88rem;
}
.footer .container { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.footer a { color: rgba(250, 242, 233, 0.85); text-decoration: none; margin-left: 20px; }
.footer a:first-child { margin-left: 0; }
.footer a:hover { color: var(--green); }

/* ---------- Responsive ---------- */

@media (max-width: 640px) {
  .hero { padding-top: 56px; }
  .section { padding: 56px 0; }
  .authors { font-size: 0.98rem; }
}