/* ==========================================================================
   LLaDA-UI project page — base.css
   Design tokens, reset, shared primitives.

   Identity: block-wise masked diffusion. Palette taken from the technical
   report itself — indigo #2A4B8C / steel #5E83B5 (the report's link colors)
   plus a warm "mask token" accent #E07A5F (the report's radar orange, echoing
   its AR-blue vs diffusion-warm table convention).
   ========================================================================== */

:root {
  --paper: #f7f8fc;
  --tint: #eceffa;
  --card: #ffffff;
  --ink: #141d31;
  --muted: #58658a;
  --line: #dce1ef;

  --indigo: #2a4b8c;
  --indigo-bright: #3e6cc4;
  --steel: #5e83b5;
  --mask: #e07a5f;
  --mask-soft: #f9e7e0;

  --tbd-ink: #6d7896;
  --tbd-bg: #f1f3fa;
  --tbd-line: #b0b9d2;
  --code-bg: #16213c;
  --code-ink: #dbe4f7;

  --font-display: "Space Grotesk", "IBM Plex Sans", system-ui, sans-serif;
  --font-body: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --radius: 16px;
  --shadow-soft: 0 10px 30px -18px rgba(42, 75, 140, 0.38);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--indigo-bright); text-decoration: none; }
a:hover { text-decoration: underline; }

:focus-visible {
  outline: 2px solid var(--indigo-bright);
  outline-offset: 3px;
  border-radius: 4px;
}

.wrap {
  max-width: 1080px;
  margin-inline: auto;
  padding-inline: 24px;
}

[hidden] { display: none !important; }

/* TBD chip — placeholder language for links pending release. */
.tbd {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--tbd-ink);
  background: var(--tbd-bg);
  border: 1px dashed var(--tbd-line);
  border-radius: 6px;
  padding: 2px 9px;
  vertical-align: middle;
}

/* Inline mask-token chip — used when the prose names the mechanism itself. */
.mask-chip {
  font-family: var(--font-mono);
  font-size: 0.82em;
  font-weight: 500;
  color: #b0532f;
  background: var(--mask-soft);
  border: 1px solid rgba(224, 122, 95, 0.45);
  border-radius: 5px;
  padding: 1px 7px;
  white-space: nowrap;
}

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

.section { padding: 76px 0 8px; }
.section:last-of-type { padding-bottom: 72px; }

.section-head { max-width: 800px; margin-bottom: 36px; }
.section-head .eyebrow { font-size: 11.5px; }
.section-head .eyebrow::after { content: none; }

.section-head h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.8rem, 3.4vw, 2.3rem);
  letter-spacing: -0.015em;
  line-height: 1.15;
  margin: 10px 0 0;
}
.section-head .lede {
  color: var(--muted);
  font-size: 16.5px;
  margin: 14px 0 0;
}
.section-head .lede strong { color: var(--ink); font-weight: 600; }

.section-footnote {
  font-size: 12.5px;
  color: var(--muted);
  margin: 16px 0 0;
}

/* --------------------------------------------------------------------------
   Scroll reveal + motion preferences
   -------------------------------------------------------------------------- */

[data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
[data-reveal].revealed { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .mtoken { animation: none; }
  [data-reveal] { opacity: 1; transform: none; transition: none; }
  .btn, .card { transition: none; }
}