/* ============================================================
   Transit Data — Neutral Elegance palette
   Warm taupe, latte beige, almond, soft rosé, dusty cocoa
   ============================================================ */

:root {
  /* core palette */
  --cream: #faf3ec;
  --almond: #f4e6d5;
  --latte: #efe1cf;
  --beige: #e4d2b8;
  --rose: #e9c8c2;
  --rose-deep: #d3a59c;
  --taupe: #a98d77;
  --taupe-deep: #8a7160;
  --cocoa: #7a5a48;
  --cocoa-deep: #5b3a2b;
  --ink: #3c2a20;
  --muted: #6e5a4c;

  /* semantic */
  --bg: var(--cream);
  --bg-alt: #fff8ef;
  --surface: #ffffff;
  --surface-soft: var(--almond);
  --border: #e2d2bc;
  --border-soft: #ecdfca;

  --link: var(--cocoa);
  --link-hover: var(--cocoa-deep);
  --accent: var(--rose-deep);
  --accent-2: var(--taupe);

  /* layout */
  --container-max: 1320px;
  --container-wide: 1480px;
  --content-max: 1100px;
  --gutter: clamp(1rem, 2.5vw, 2rem);
  --header-h: 72px;

  /* type */
  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --font-serif: "Source Serif Pro", "Iowan Old Style", Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, "JetBrains Mono", "Fira Code", Menlo, Consolas, monospace;

  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 18px;
  --shadow-sm: 0 1px 2px rgba(91, 58, 43, 0.05), 0 2px 6px rgba(91, 58, 43, 0.04);
  --shadow: 0 4px 12px rgba(91, 58, 43, 0.08), 0 8px 24px rgba(91, 58, 43, 0.06);
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.8;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

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

a {
  color: var(--link);
  text-decoration: none;
  background-image: linear-gradient(currentColor, currentColor);
  background-size: 0 1.5px;
  background-repeat: no-repeat;
  background-position: 0 100%;
  transition: background-size 250ms ease, color 200ms ease;
}
a:hover, a:focus-visible { color: var(--link-hover); background-size: 100% 1.5px; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }

.skip-link {
  position: absolute; left: -9999px; top: 8px;
  background: var(--cocoa-deep); color: #fff;
  padding: 8px 14px; border-radius: var(--radius-sm);
}
.skip-link:focus { left: 8px; z-index: 1000; }

.layout {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.main { flex: 1; }

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.container--wide { max-width: var(--container-wide); }

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 243, 236, 0.92);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--border-soft);
  min-height: var(--header-h);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  min-height: var(--header-h);
}

.site-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  background: none !important;
  color: var(--ink);
}
.site-logo:hover { color: var(--cocoa-deep); }
.site-logo__mark {
  width: 44px; height: 44px;
  display: inline-grid; place-items: center;
  transition: transform 300ms ease;
}
.site-logo__mark svg { width: 100%; height: 100%; }
.site-logo:hover .site-logo__mark { transform: rotate(-6deg) scale(1.05); }
.site-logo__mark--sm { width: 36px; height: 36px; }
.site-logo__text { display: flex; flex-direction: column; line-height: 1.1; }
.site-logo__primary { font-weight: 700; font-size: 1.05rem; letter-spacing: 0.01em; color: var(--cocoa-deep); }
.site-logo__secondary { font-size: 0.78rem; color: var(--muted); letter-spacing: 0.04em; text-transform: uppercase; }

.site-nav__list {
  list-style: none; margin: 0; padding: 0;
  display: flex; align-items: center; gap: 0.25rem;
}
.site-nav__link {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.55rem 0.9rem;
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--ink);
  background: none !important;
  transition: background-color 200ms ease, color 200ms ease, transform 200ms ease;
}
.site-nav__link:hover {
  background-color: var(--almond) !important;
  color: var(--cocoa-deep);
}
.site-nav__link.is-current {
  background-color: var(--latte) !important;
  color: var(--cocoa-deep);
  box-shadow: inset 0 0 0 1px var(--beige);
}
.site-nav__icon {
  width: 18px; height: 18px; fill: currentColor; opacity: 0.85;
}

.nav-toggle {
  display: none;
  background: transparent; border: 1px solid var(--border);
  width: 42px; height: 42px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  padding: 10px;
  flex-direction: column; justify-content: space-between;
}
.nav-toggle__bar { display: block; height: 2px; background: var(--cocoa); border-radius: 2px; transition: transform 200ms; }

@media (max-width: 860px) {
  .nav-toggle { display: flex; }
  .site-nav {
    position: absolute;
    top: var(--header-h); left: 0; right: 0;
    background: var(--cream);
    border-bottom: 1px solid var(--border-soft);
    box-shadow: var(--shadow);
    display: none;
    padding: 0.75rem var(--gutter) 1rem;
  }
  .site-nav.is-open { display: block; }
  .site-nav__list { flex-direction: column; align-items: stretch; gap: 0.25rem; }
  .site-nav__link { padding: 0.75rem 0.9rem; }
}

/* ---------- footer ---------- */
.site-footer {
  margin-top: 4rem;
  background: linear-gradient(180deg, var(--almond), var(--latte));
  border-top: 1px solid var(--border);
  color: var(--cocoa-deep);
}
.site-footer__inner {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 2rem;
  padding-block: 2.5rem;
}
.site-footer__brand { display: flex; align-items: center; gap: 0.75rem; }
.site-footer__tagline { margin: 0; font-weight: 600; color: var(--cocoa-deep); }
.site-footer__heading { margin: 0 0 0.75rem; font-size: 0.78rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); }
.site-footer__nav ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 0.4rem; }
.site-footer__nav a { color: var(--cocoa); }
.site-footer__meta { font-size: 0.92rem; color: var(--muted); }
.site-footer__copy { margin-top: 1rem; font-size: 0.85rem; }
@media (max-width: 720px) {
  .site-footer__inner { grid-template-columns: 1fr; }
}

/* ============================================================
   Front page
   ============================================================ */
.hero {
  padding: clamp(2.5rem, 6vw, 5rem) 0 clamp(2rem, 4vw, 3.5rem);
  background:
    radial-gradient(1200px 500px at 100% -10%, rgba(233, 200, 194, 0.45), transparent 60%),
    radial-gradient(900px 400px at -10% 110%, rgba(169, 141, 119, 0.25), transparent 60%);
}
.hero__inner {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: clamp(1.5rem, 4vw, 4rem);
  align-items: center;
}
@media (max-width: 920px) { .hero__inner { grid-template-columns: 1fr; } }

.hero__eyebrow {
  display: inline-block;
  font-size: 0.78rem; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--cocoa); background: var(--almond);
  padding: 0.35rem 0.75rem; border-radius: 999px; border: 1px solid var(--border);
}
.hero__title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4.5vw, 3.5rem);
  line-height: 1.1;
  margin: 1rem 0 1.25rem;
  color: var(--cocoa-deep);
  letter-spacing: -0.01em;
}
.hero__title em {
  font-style: normal;
  background: linear-gradient(90deg, var(--cocoa), var(--rose-deep));
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.hero__lede { font-size: 1.1rem; line-height: 1.75; color: var(--muted); max-width: 60ch; margin: 0 0 1.5rem; }
.hero__lede + .hero__lede { margin-top: 0; }

.cta-row { display: flex; flex-wrap: wrap; gap: 0.85rem; margin-top: 1.75rem; }
.cta {
  --cta-bg: var(--surface);
  --cta-fg: var(--cocoa-deep);
  display: inline-flex; align-items: center; gap: 0.6rem;
  padding: 0.85rem 1.15rem;
  background: var(--cta-bg) !important;
  color: var(--cta-fg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 600;
  box-shadow: var(--shadow-sm);
  transition: transform 220ms ease, box-shadow 220ms ease, background 220ms ease, color 220ms ease;
}
.cta:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  color: var(--cocoa-deep);
}
.cta--primary { --cta-bg: var(--cocoa); --cta-fg: #fff8ef; border-color: var(--cocoa); }
.cta--primary:hover { --cta-bg: var(--cocoa-deep); color: #fff8ef; }
.cta--rose { --cta-bg: var(--rose); --cta-fg: var(--cocoa-deep); border-color: var(--rose-deep); }
.cta--almond { --cta-bg: var(--almond); --cta-fg: var(--cocoa-deep); border-color: var(--beige); }
.cta__icon {
  width: 22px; height: 22px;
  display: inline-grid; place-items: center;
  border-radius: 6px;
  background: rgba(255,255,255,0.4);
}
.cta--primary .cta__icon { background: rgba(255,255,255,0.15); }
.cta__icon svg { width: 16px; height: 16px; fill: currentColor; }

.hero__visual {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow);
}
.hero__visual h3 { margin-top: 0; color: var(--cocoa-deep); font-family: var(--font-serif); }
.hero__visual ul { margin: 0; padding-left: 1.25rem; }
.hero__visual li { margin: 0.4rem 0; color: var(--muted); }
.hero__visual li strong { color: var(--ink); }

/* Pillars / topic cards */
.section { padding-block: clamp(2.5rem, 5vw, 4rem); }
.section__head { max-width: 780px; margin-bottom: 2rem; }
.section__eyebrow {
  font-size: 0.78rem; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--rose-deep); font-weight: 600;
}
.section__title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 2.8vw, 2.25rem);
  margin: 0.4rem 0 0.6rem; color: var(--cocoa-deep);
}
.section__lede { color: var(--muted); margin: 0; }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex; flex-direction: column;
  transition: transform 220ms ease, box-shadow 220ms ease, border-color 220ms ease;
  box-shadow: var(--shadow-sm);
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: var(--beige);
}
.card__icon {
  width: 46px; height: 46px;
  display: grid; place-items: center;
  border-radius: 12px;
  margin-bottom: 1rem;
}
.card__icon svg { width: 26px; height: 26px; fill: var(--cocoa-deep); }
.card--rose .card__icon { background: var(--rose); }
.card--almond .card__icon { background: var(--almond); }
.card--latte .card__icon { background: var(--latte); }
.card__title { margin: 0 0 0.5rem; color: var(--cocoa-deep); font-size: 1.15rem; }
.card__title a { color: inherit; }
.card__blurb { margin: 0; color: var(--muted); font-size: 0.97rem; }
.card__more { margin-top: 1rem; font-weight: 600; color: var(--cocoa); }
.card__more::after { content: " →"; transition: transform 200ms ease; display: inline-block; }
.card:hover .card__more::after { transform: translateX(4px); }

/* ============================================================
   Content pages
   ============================================================ */
.content-page { padding: 2rem 0 3rem; }
.content-page__layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: clamp(1.5rem, 3vw, 3rem);
  align-items: start;
}
@media (max-width: 1080px) { .content-page__layout { grid-template-columns: 1fr; } }

.breadcrumbs {
  font-size: 0.88rem;
  color: var(--muted);
  display: flex; flex-wrap: wrap; gap: 0.4rem;
  margin-bottom: 1.5rem;
  list-style: none; padding: 0;
}
.breadcrumbs li { display: inline-flex; align-items: center; gap: 0.4rem; }
.breadcrumbs li + li::before {
  content: "›"; color: var(--taupe); margin-right: 0.4rem;
}
.breadcrumbs a { color: var(--cocoa); }
.breadcrumbs li:last-child { color: var(--ink); font-weight: 500; }

.prose {
  max-width: var(--content-max);
  line-height: 1.8;
}
.prose h1 {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4vw, 2.8rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--cocoa-deep);
  margin: 0 0 2rem;
  background: linear-gradient(90deg, var(--cocoa-deep) 0%, var(--rose-deep) 100%);
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.prose h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.4rem, 2.4vw, 1.85rem);
  line-height: 1.3;
  color: var(--cocoa-deep);
  margin: 3.5rem 0 1.4rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border-soft);
}
.prose h3 {
  font-family: var(--font-serif);
  font-size: clamp(1.15rem, 1.8vw, 1.4rem);
  line-height: 1.35;
  color: var(--cocoa);
  margin: 2.75rem 0 1rem;
}
.prose h4 {
  font-size: 1.05rem;
  color: var(--cocoa-deep);
  margin: 2rem 0 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.prose p { margin: 0 0 1.5rem; }
.prose ul, .prose ol { margin: 0 0 1.75rem; padding-left: 1.4rem; }
.prose li { margin: 0.55rem 0; }
.prose li > p { margin-bottom: 0.5rem; }
.prose strong { color: var(--cocoa-deep); }
.prose hr { border: none; border-top: 1px solid var(--border-soft); margin: 3rem 0; }
.prose blockquote {
  margin: 2rem 0;
  padding: 1.25rem 1.5rem;
  background: var(--almond);
  border-left: 4px solid var(--rose-deep);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--muted);
}
.prose blockquote p:last-child { margin-bottom: 0; }

/* anchor links from markdown-it-anchor permalink.headerLink wrap the heading */
.prose h2 a, .prose h3 a, .prose h4 a { color: inherit; background: none !important; }
.prose h2 a:hover, .prose h3 a:hover, .prose h4 a:hover { color: var(--rose-deep); }

/* inline code — subtle, blends with surrounding text */
.prose :not(pre) > code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: rgba(169, 141, 119, 0.08);
  color: var(--cocoa);
  padding: 0.05em 0.25em;
  border-radius: 3px;
  border: none;
  font-weight: 400;
}
.prose a > code,
.prose :not(pre) > code:where(a *) { color: inherit; }

/* tables */
.prose .table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 1.5rem 0;
  background: var(--surface);
  -webkit-overflow-scrolling: touch;
}
.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}
.prose thead th {
  background: var(--almond);
  color: var(--cocoa-deep);
  font-weight: 700;
  text-align: left;
  padding: 0.95rem 1.15rem;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
.prose tbody td {
  padding: 0.95rem 1.15rem;
  border-bottom: 1px solid var(--border-soft);
  vertical-align: top;
  line-height: 1.6;
}
.prose tbody tr:last-child td { border-bottom: none; }
.prose tbody tr:nth-child(even) td { background: rgba(244, 230, 213, 0.25); }

/* code blocks */
.code-block {
  margin: 2rem 0;
  background: #fdf6ec;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.code-block__header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.4rem 0.85rem;
  background: var(--almond);
  border-bottom: 1px solid var(--border);
  font-size: 0.78rem;
}
.code-block__lang {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--cocoa-deep); font-weight: 700;
}
.code-block__copy {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--cocoa-deep);
  padding: 0.25rem 0.65rem;
  border-radius: 6px;
  font: inherit;
  font-size: 0.78rem;
  cursor: pointer;
  transition: background 180ms ease, color 180ms ease;
}
.code-block__copy:hover { background: var(--cocoa); color: #fff8ef; }
.code-block__copy.is-copied { background: var(--rose-deep); color: #fff; border-color: var(--rose-deep); }

.code-block pre {
  margin: 0;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  background: transparent;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  line-height: 1.55;
  color: var(--ink);
}
.code-block code { font-family: inherit; background: none; padding: 0; color: inherit; }

/* Prism light theme tuned to palette */
.token.comment, .token.prolog, .token.doctype, .token.cdata { color: #8a7160; font-style: italic; }
.token.punctuation { color: #6e5a4c; }
.token.namespace { opacity: 0.7; }
.token.property, .token.tag, .token.boolean, .token.number, .token.constant, .token.symbol { color: #b56353; }
.token.selector, .token.attr-name, .token.string, .token.char, .token.builtin, .token.inserted { color: #7c5e2c; }
.token.operator, .token.entity, .token.url, .language-css .token.string, .style .token.string { color: #8a6f3d; background: none; }
.token.atrule, .token.attr-value, .token.keyword { color: #7a5a48; font-weight: 600; }
.token.function, .token.class-name { color: #8d4a3c; }
.token.regex, .token.important, .token.variable { color: #b56353; }
.token.important, .token.bold { font-weight: 700; }
.token.italic { font-style: italic; }

/* task / checkbox lists */
.task-item { list-style: none; margin-left: -1.4rem; padding-left: 0; }
.task-item__label {
  display: inline-flex; align-items: flex-start; gap: 0.65rem;
  cursor: pointer;
  padding: 0.3rem 0;
  line-height: 1.7;
}
.task-item__checkbox {
  appearance: none;
  -webkit-appearance: none;
  width: 18px; height: 18px;
  margin-top: 0.32em;
  border: 1.5px solid var(--taupe);
  border-radius: 4px;
  background: var(--surface);
  display: inline-grid; place-items: center;
  cursor: pointer;
  transition: border-color 150ms ease, background-color 150ms ease;
  flex-shrink: 0;
}
.task-item__checkbox:hover { border-color: var(--cocoa); }
.task-item__checkbox:checked { background: var(--cocoa); border-color: var(--cocoa); }
.task-item__checkbox:checked::after {
  content: ""; width: 5px; height: 9px;
  border: solid #fff8ef;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg) translate(-1px, -1px);
}
.task-item__checkbox:checked + .task-item__text {
  text-decoration: line-through;
  color: var(--muted);
}
.task-item__text { transition: color 150ms ease; }
.prose ul:has(> .task-item) { padding-left: 0; }

/* mermaid */
.mermaid {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin: 1.5rem 0;
  text-align: center;
  overflow-x: auto;
}

/* FAQ accordions */
.prose details.faq, .prose details.faq-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0;
  margin: 0.75rem 0;
  overflow: hidden;
  transition: border-color 200ms ease, box-shadow 200ms ease;
}
.prose details.faq[open], .prose details.faq-item[open] {
  border-color: var(--rose-deep);
  box-shadow: var(--shadow-sm);
}
.prose details.faq > summary, .prose details.faq-item > summary {
  list-style: none;
  cursor: pointer;
  padding: 1rem 1.15rem;
  font-weight: 600;
  color: var(--cocoa-deep);
  background: var(--almond);
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem;
}
.prose details.faq > summary::-webkit-details-marker,
.prose details.faq-item > summary::-webkit-details-marker { display: none; }
.prose details.faq > summary::after,
.prose details.faq-item > summary::after {
  content: "+";
  font-size: 1.4rem; line-height: 1; color: var(--cocoa);
  transition: transform 200ms ease;
}
.prose details.faq[open] > summary::after,
.prose details.faq-item[open] > summary::after { transform: rotate(45deg); }
.prose details.faq > div, .prose details.faq-item > div,
.prose details.faq > p, .prose details.faq-item > p { padding: 1rem 1.15rem; margin: 0; }

/* in-page anchor link hover */
.prose h2:hover a::after, .prose h3:hover a::after { opacity: 1; }

/* ---------- right rail ---------- */
.side-rail {
  position: sticky;
  top: calc(var(--header-h) + 1rem);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  font-size: 0.93rem;
  box-shadow: var(--shadow-sm);
}
.side-rail h2 {
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--rose-deep);
  margin: 0 0 0.75rem;
}
.side-rail ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 0.4rem; }
.side-rail a { color: var(--cocoa); }
.side-rail a.is-current { color: var(--cocoa-deep); font-weight: 600; }
.side-rail__group + .side-rail__group { margin-top: 1.25rem; padding-top: 1.25rem; border-top: 1px solid var(--border-soft); }
@media (max-width: 1080px) {
  .side-rail { position: static; }
}

/* small */
.kicker { display: inline-block; font-size: 0.78rem; color: var(--rose-deep); letter-spacing: 0.1em; text-transform: uppercase; font-weight: 600; }

/* selection */
::selection { background: var(--rose); color: var(--cocoa-deep); }