/* Values come from website/STYLE_GUIDE.md. Change the guide first, then this file. */

:root {
  --ink: #1F1D1A;
  --muted: #5C574F;
  --border: #D9D4CA;
  --surface: #F7F5F0;
  --paper: #FFFFFF;

  --root-brown: #6B3A2A;
  --branch-amber: #D97706;
  --leaf-green: #2D7D46;
  --fruit-indigo: #4A5BAF;

  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "Cascadia Mono", "SF Mono", Menlo, Consolas, monospace;

  --text-body: 18px;
  --text-small: 15px;
  --text-h1: 36px;
  --text-h2: 27px;
  --text-h3: 21px;
  --text-summary: 21px;

  --measure: 70ch;
  --space: 1.5rem;
}

@media (max-width: 800px) {
  :root {
    --text-body: 17px;
    --text-h1: 30px;
    --text-h2: 24px;
    --text-h3: 19px;
    --text-summary: 19px;
  }
}

/* Base */

*, *::before, *::after { box-sizing: border-box; }

html { font-size: var(--text-body); }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  line-height: 1.6;
  text-align: left;
}

h1, h2, h3 { color: var(--ink); text-wrap: balance; }
h1 { font-size: var(--text-h1); font-weight: 700; line-height: 1.2; margin: 0 0 0.5rem; }
h2 { font-size: var(--text-h2); font-weight: 700; line-height: 1.25; margin: 3rem 0 1rem; }
h3 { font-size: var(--text-h3); font-weight: 600; line-height: 1.3; margin: 2rem 0 0.75rem; }

p, ul, ol, dl, table, figure { margin: 0 0 var(--space); }

a { color: var(--leaf-green); text-decoration: underline; text-underline-offset: 0.15em; }
a:hover { color: var(--root-brown); }
a[href^="http"]::after { content: " \2197"; font-size: 0.8em; }

:focus-visible { outline: 2px solid var(--leaf-green); outline-offset: 2px; }

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--surface);
  padding: 0.1em 0.3em;
  border-radius: 3px;
}

/* Code blocks: literal text to copy, such as attribution lines. Lines wrap instead of scrolling. */
pre {
  background: var(--surface);
  padding: 0.75rem 1rem;
  border-radius: 4px;
  font-size: var(--text-small);
  line-height: 1.5;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}
pre code { background: none; padding: 0; font-size: 1em; }

.contributors { margin-top: 0; }

hr { border: 0; border-top: 1px solid var(--border); margin: 3rem 0; }

.page-summary {
  font-size: var(--text-summary);
  line-height: 1.45;
  color: var(--muted);
  margin-bottom: 2.5rem;
}

.skip-link {
  position: absolute;
  left: -9999px;
}
.skip-link:focus {
  left: 1rem;
  top: 1rem;
  background: var(--paper);
  padding: 0.5rem 1rem;
  z-index: 10;
}

/* Header and footer */

.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--paper);
}

.site-header-inner {
  max-width: 1320px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 2.5rem;
}

.site-title {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink);
  font-weight: 700;
  font-size: 1.1rem;
  text-decoration: none;
}
.site-title:hover { color: var(--root-brown); }
/* The brand mark: 32px in the header. Never smaller than 16px (style guide, Section 5.7). */
.site-mark { display: block; width: 32px; height: 32px; flex: none; }

.site-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.5rem;
}

.site-nav a {
  color: var(--ink);
  text-decoration: none;
  font-size: var(--text-small);
  padding-bottom: 0.2rem;
  border-bottom: 2px solid transparent;
}
.site-nav a:hover { color: var(--root-brown); border-bottom-color: var(--border); }
.site-nav a[aria-current] { color: var(--root-brown); font-weight: 600; border-bottom-color: var(--root-brown); }

.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 4rem;
  padding: 1.5rem max(1.5rem, calc((100% - 1320px) / 2 + 1.5rem));
  font-size: var(--text-small);
  color: var(--muted);
}
.site-footer p { margin: 0; }

/* Three-column page layout */

.page-grid {
  max-width: 1320px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 0;
  display: grid;
  grid-template-columns: 15rem minmax(0, var(--measure)) 13rem;
  gap: 3rem;
  justify-content: center;
}

.content { min-width: 0; max-width: var(--measure); }

.sidebar, .toc-column {
  position: sticky;
  top: 1.5rem;
  align-self: start;
  max-height: calc(100vh - 3rem);
  overflow-y: auto;
  font-size: var(--text-small);
  line-height: 1.5;
}

.sidebar { background: var(--surface); padding: 1.25rem; border-radius: 4px; }
.sidebar ul, .section-menu ul, .toc ul { list-style: none; margin: 0 0 1rem; padding: 0; }
.sidebar li, .section-menu li, .toc li { margin: 0.3rem 0; }
.sidebar a, .section-menu a, .toc a { color: var(--ink); text-decoration: none; }
.sidebar a:hover, .section-menu a:hover, .toc a:hover { color: var(--root-brown); text-decoration: underline; }
.sidebar a[aria-current="page"], .section-menu a[aria-current="page"] { color: var(--root-brown); font-weight: 600; }

.sidebar-title { font-weight: 700; margin-bottom: 1rem; }
.sidebar-group, .toc-title {
  color: var(--muted);
  font-weight: 600;
  margin: 1.25rem 0 0.4rem;
}
.toc-title { margin-top: 0; }

.section-menu { display: none; }

@media (max-width: 1150px) {
  .page-grid { grid-template-columns: 14rem minmax(0, var(--measure)); }
  .toc-column { display: none; }
}

@media (max-width: 800px) {
  .page-grid { display: block; padding-top: 1.5rem; }
  .sidebar { display: none; }
  .section-menu {
    display: block;
    background: var(--surface);
    border: 1px solid var(--muted);
    border-radius: 4px;
    padding: 0.75rem 1rem;
    margin-bottom: 2rem;
    font-size: var(--text-small);
  }
  .section-menu summary { cursor: pointer; font-weight: 600; }
  table { display: block; overflow-x: auto; }
  /* Diagrams keep a readable size and scroll sideways instead of shrinking. */
  figure.diagram { overflow-x: auto; }
  figure.diagram svg { min-width: var(--diagram-min); }
  .section-menu[open] summary { margin-bottom: 1rem; }
}

/* Home */

.home {
  max-width: 60rem;
  margin: 0 auto;
  padding: 3rem 1.5rem 0;
}
.home > p, .home > ul { max-width: var(--measure); }

/* The full tree illustration appears here and nowhere else on the site. */
.home-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 20rem;
  align-items: center;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}
.home-hero .page-summary { margin-bottom: 0; }
.home-hero-image { display: block; width: 100%; height: auto; }

@media (max-width: 800px) {
  .home-hero { grid-template-columns: minmax(0, 1fr); gap: 1rem; }
  .home-hero-image { width: 11rem; order: -1; }
}

.entry-points {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  gap: 1.25rem;
}
.entry-points li {
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1.25rem;
}
.entry-points h3 { margin-top: 0; }
.entry-points p { margin-bottom: 0.75rem; }
.entry-points p:last-child { margin-bottom: 0; }

/* Components */

.callout {
  background: var(--surface);
  border-left: 4px solid var(--border);
  padding: 1rem 1.25rem;
  margin: 0 0 var(--space);
  border-radius: 0 4px 4px 0;
}
.callout > :last-child { margin-bottom: 0; }
.callout-tip { border-left-color: var(--leaf-green); }
.callout-trap { border-left-color: var(--root-brown); }
.callout-label { font-weight: 700; margin-bottom: 0.4rem; }

/* Facilitator script: words said out loud. Written as a Markdown blockquote. */
blockquote {
  margin: 0 0 var(--space) 1.5rem;
  padding: 0.25rem 0 0.25rem 1.25rem;
  border-left: 3px solid var(--muted);
  font-style: italic;
}
blockquote > :last-child { margin-bottom: 0; }

table { border-collapse: collapse; width: 100%; font-size: var(--text-small); }
th, td { text-align: left; vertical-align: top; padding: 0.6rem 0.75rem; border-bottom: 1px solid var(--border); }
th { background: var(--surface); font-weight: 600; }
.table-scroll { overflow-x: auto; }

figure.diagram { margin: 2rem 0 0.5rem; }
figure.diagram svg { display: block; width: 100%; height: auto; }
figure.diagram figcaption { font-size: var(--text-small); color: var(--muted); margin-top: 0.5rem; }

/* Text version of a diagram, for screen readers and for anyone who prefers reading. */
.diagram-text { font-size: var(--text-small); margin: 0 0 2rem; }
.diagram-text summary { color: var(--muted); cursor: pointer; }
.diagram-text summary:hover { color: var(--root-brown); }
.diagram-text[open] { background: var(--surface); padding: 0.75rem 1rem; border-radius: 4px; }
.diagram-text p { margin: 0.75rem 0 0.25rem; font-weight: 600; }
.diagram-text ul { margin: 0; }

.section-list dl { margin: 0 0 2rem; }
.section-list dt { font-weight: 600; margin-top: 1rem; }
.section-list dd { margin: 0.2rem 0 0; color: var(--muted); }

/* Glossary */
.glossary-letters { display: flex; flex-wrap: wrap; gap: 0.25rem 0.9rem; margin: 0 0 1rem; font-weight: 600; }
.glossary-letters a { text-decoration: none; }
.glossary-letters a:hover { text-decoration: underline; }
dl.glossary { margin: 0 0 1rem; }
dl.glossary dt { font-weight: 700; margin-top: 1.25rem; scroll-margin-top: 1rem; }
dl.glossary dd { margin: 0.25rem 0 0; }
dl.glossary dd.glossary-alias { color: var(--muted); }

.related { margin-top: 3rem; }
.related h2 { font-size: var(--text-h3); margin-top: 0; }

.pager {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}
.pager a { display: block; max-width: 48%; text-decoration: none; font-weight: 600; }
.pager a span { display: block; font-size: var(--text-small); font-weight: 400; color: var(--muted); }
.pager-next { margin-left: auto; text-align: right; }