:root {
  --bg: #ffffff;
  --fg: #111111;
  --dim: #6b6f78;
  --line: #e5e5e5;
  --accent: #2563eb;
  --box-bg: #fafbfc;
  --code-bg: #f5f5f5;
  --loop-depth-1: #64a7cd;
  --loop-depth-2: #55b99b;
  --loop-depth-3: #c6a056;
  --loop-depth-4: #a28bc3;
  --diagram-font: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
.depth-1 { --depth-color: var(--loop-depth-1); }
.depth-2 { --depth-color: var(--loop-depth-2); }
.depth-3 { --depth-color: var(--loop-depth-3); }
.depth-4 { --depth-color: var(--loop-depth-4); }
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0b0d;
    --fg: #e8e6e0;
    --dim: #a0a6b0;
    --line: #2a2e36;
    --accent: #6aa9ff;
    --box-bg: #11141a;
    --code-bg: #14171e;
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { background: var(--bg); }
body {
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  min-height: 100vh;
}
a { color: inherit; text-decoration: none; }
a:hover { color: var(--accent); }
em { font-style: italic; }
strong { font-weight: 600; }

/* back link */
.backlink {
  position: fixed;
  top: 20px;
  left: 24px;
  z-index: 11;
  font-size: 13px;
  color: var(--dim);
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--bg);
  transition: border-color 0.2s, color 0.2s;
}
.backlink:hover { color: var(--accent); border-color: var(--accent); }

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 100px 40px 80px;
}

/* hero */
.hero { text-align: center; margin-bottom: 72px; }
.hero h1 {
  font-size: 44px;
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}
.hero h2 {
  font-size: 24px;
  font-weight: 400;
  color: var(--dim);
  line-height: 1.35;
  margin-bottom: 12px;
}
.hero .venue {
  color: var(--accent);
  font-size: 14px;
  margin-bottom: 24px;
}
.authors {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 2px 8px;
  font-size: 16px;
  margin-bottom: 6px;
}
.authors .author { white-space: nowrap; }
.author-separator { color: var(--dim); }
.authors sup { font-size: 11px; color: var(--dim); }
.authors a {
  color: var(--fg);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s, color 0.2s;
}
.authors a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.affiliations {
  font-size: 13px;
  color: var(--dim);
  margin-bottom: 28px;
}
.affiliations sup { color: var(--accent); }

.links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}
.links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 18px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 14px;
  color: var(--fg);
  transition: border-color 0.2s, color 0.2s;
}
.links a:hover { border-color: var(--accent); color: var(--accent); }
.links svg { width: 16px; height: 16px; flex-shrink: 0; }
.links .ai { font-size: 18px; line-height: 1; }
.links .hf { font-size: 16px; line-height: 1; }

/* paper links */
.paper-cta { margin-top: 32px; text-align: center; }
.paper-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 11px 22px;
  border: 1px solid var(--accent);
  border-radius: 999px;
  background: var(--accent);
  color: var(--bg);
  font-size: 14px;
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
}
.paper-link:hover { background: var(--bg); color: var(--accent); }
.paper-link:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }

/* sections */
section {
  margin-bottom: 48px;
}
section.narrow {
  max-width: 820px;
  margin-left: auto;
  margin-right: auto;
}
h3.section-title {
  font-size: 28px;
  font-weight: 600;
  text-align: center;
  margin-bottom: 24px;
  letter-spacing: -0.015em;
}

p, ul { margin-bottom: 14px; }
p:last-child, ul:last-child { margin-bottom: 0; }
ul { padding-left: 22px; }
li { margin-bottom: 8px; }
.prose { color: var(--fg); }
.prose p:not(.center-eq, .blocks-heading-label),
.intro-copy p,
.chapter-explanation,
:is(.cdb-component, .project-card) > p {
  text-align: justify;
  -webkit-hyphens: auto;
  hyphens: auto;
}

/* boxes */
.box {
  background: var(--box-bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 20px 22px;
}
.box.accent {
  border-left: 3px solid var(--accent);
}

/* diagrams */
.project-diagram { display: block; width: 100%; height: auto; }
.project-diagram text { fill: var(--fg); font-family: var(--diagram-font); font-size: 14px; text-anchor: middle; }
.project-diagram .diagram-label { fill: var(--dim); font-size: 12px; }
.project-diagram .diagram-small { font-size: 12px; }
.project-diagram .diagram-box { fill: var(--bg); stroke: var(--line); stroke-width: 1; }
.project-diagram .diagram-depth rect { fill: color-mix(in srgb, var(--depth-color) 28%, var(--bg)); stroke: var(--depth-color); }
.project-diagram .diagram-box.diagram-token, .demo .stage-box.diagram-token { fill: color-mix(in srgb, var(--dim) 20%, var(--bg)); stroke: var(--dim); }
.project-diagram .diagram-wire { fill: none; stroke: var(--dim); stroke-width: 1; }
.project-diagram .diagram-feedback { stroke-dasharray: 3 4; }
.project-diagram .diagram-arrow-tip { fill: var(--dim); }
.project-diagram .diagram-loop { fill: none; stroke: var(--loop-depth-2); stroke-width: 1.3; }
.project-diagram .diagram-loop-tip { fill: var(--loop-depth-2); }
.project-diagram .diagram-loop-label { fill: var(--loop-depth-2); font-size: 12px; }

/* bibtex */
.bibtex-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}
.bibtex-header h4 { font-size: 14px; font-weight: 500; margin-bottom: 0; }
.copy-btn {
  background: var(--bg);
  color: var(--fg);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 6px 12px;
  font-size: 12px;
  font-family: inherit;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s, background 0.2s;
}
.copy-btn:hover { border-color: var(--accent); color: var(--accent); }
.copy-btn.copied { color: #3fdb7c; border-color: #3fdb7c; }
pre.bibtex {
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 16px;
  overflow-x: auto;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
  color: var(--fg);
}

/* responsive */
@media (max-width: 760px) {
  main { padding: 90px 20px 60px; }
  .hero h1 { font-size: 28px; }
  .hero h2 { font-size: 17px; }
  h3.section-title { font-size: 19px; }
}

.explainer { scroll-margin-top: 80px; }
main > .chapter > h3.section-title { font-size: 34px; line-height: 1.25; padding-bottom: 24px; border-bottom: 1px solid var(--line); }
.chapter-content { width: calc(100% - 64px); max-width: 920px; margin-inline: auto; }
.citation-box { width: 100%; max-width: 820px; margin-inline: auto; padding-top: 16px; }
main > .chapter { margin-bottom: 112px; scroll-margin-top: 80px; }
main > .chapter[tabindex="-1"]:focus { outline: none; }
.opening-chapter {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 32px;
  min-height: calc(100vh - 100px);
  min-height: calc(100svh - 100px);
  padding-block: 12px 32px;
}
.opening-chapter > .hero { margin-bottom: 0; }
.opening-chapter > .narrow { width: 100%; margin-bottom: 0; }
.chapter-link { align-self: center; }
.summary-title { margin-bottom: 10px; font-size: 14px; font-weight: 600; }
.abstract-disclosure { margin-top: 18px; padding-top: 14px; border-top: 1px solid var(--line); }
.abstract-disclosure summary { display: flex; align-items: center; gap: 8px; width: fit-content; color: var(--accent); font-size: 14px; cursor: pointer; list-style: none; }
.abstract-disclosure summary::-webkit-details-marker { display: none; }
.abstract-disclosure summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; border-radius: 2px; }
.abstract-disclosure summary svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 1.5; transition: transform 180ms ease; }
.abstract-hide, .abstract-disclosure[open] .abstract-show { display: none; }
.abstract-disclosure[open] .abstract-hide { display: inline; }
.abstract-disclosure[open] summary svg { transform: rotate(180deg); }
.abstract-body { padding-top: 20px; }
.abstract-body h4 { margin-bottom: 12px; font-size: 16px; font-weight: 600; }
.abstract-disclosure[open] .abstract-body { animation: abstract-reveal 180ms ease-out; }
@keyframes abstract-reveal {
  from { opacity: 0; transform: translateY(-3px); }
  to { opacity: 1; transform: translateY(0); }
}
@media (max-width: 760px) {
  .opening-chapter { min-height: calc(100vh - 90px); min-height: calc(100svh - 90px); }
}
@media (prefers-reduced-motion: reduce) {
  .abstract-disclosure summary svg { transition: none; }
  .abstract-disclosure[open] .abstract-body { animation: none; }
}

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
@media (max-width: 800px) {
  main > .chapter > h3.section-title { font-size: 24px; }
  .chapter-content { width: calc(100% - 16px); }
  main > .chapter { margin-bottom: 80px; }
  body > .backlink { position: absolute; }
}

/* Shared explainer layouts */
.chapter-explanation { margin-bottom: 36px; line-height: 1.7; }
:is(.cdb-components, .project-cards) { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin-bottom: 36px; }
:is(.cdb-component, .project-card) { display: flex; flex-direction: column; padding: 20px; border: 1px solid var(--line); border-radius: 8px; background: var(--box-bg); color: var(--fg); }
:is(.cdb-component, .project-card) h4 { margin: 0 0 10px; font-size: 15px; line-height: 1.4; font-weight: 600; }
:is(.cdb-component, .project-card) p { margin: 0 0 16px; color: var(--dim); font-size: 14px; line-height: 1.6; }
:is(.decoding-intro, .project-intro) { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr); align-items: center; gap: 28px; }
.intro-copy { font-size: 16px; line-height: 1.7; }
@media (max-width: 800px) {
  :is(.cdb-components, .project-cards, .decoding-intro, .project-intro) { grid-template-columns: 1fr; }
}

.blocks-heading { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px 20px; margin-bottom: 16px; }
.blocks-heading-label { flex: 1 1 300px; min-width: 0; margin: 0; font-size: 15px; font-weight: 600; line-height: 1.5; }