/* Excel AI Studio, static site. Jade and cool paper; shared by every page.
   Tokens match the app's design spec. No JS, no external fonts (CSP). */
@font-face {
  font-family: "Source Serif 4";
  src: url("/fonts/SourceSerif4-latin-var.woff2") format("woff2");
  font-weight: 200 900;
  font-style: normal;
  font-display: swap;
}
:root {
  color-scheme: light dark;
  --bg: #f4f8f7;
  --surface: #ffffff;
  --surface-2: #eaf2ef;
  --ink: #172e2a;
  --ink-muted: #526b64;
  --line: #dae6e1;
  --line-strong: #bed1c8;
  --accent: #176b55;
  --accent-hover: #105440;
  --accent-soft: #e0f2e9;
  --on-accent: #ffffff;
  --warn: #b7791f;
  --focus: 0 0 0 3px rgba(23, 107, 85, 0.28);
  --r-s: 8px;
  --r-m: 16px;
  --shadow: 0 4px 8px rgb(23 46 42 / 0.04), 0 24px 64px -20px rgb(23 46 42 / 0.2);
  --ease: 180ms cubic-bezier(0.2, 0.7, 0.2, 1);
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Consolas, "Liberation Mono", monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101e1c;
    --surface: #172a26;
    --surface-2: #203630;
    --ink: #e6f2ed;
    --ink-muted: #a2bdb2;
    --line: #2d4840;
    --line-strong: #426055;
    --accent: #7dd3ae;
    --accent-hover: #9be2c2;
    --accent-soft: #234438;
    --on-accent: #102b20;
    --warn: #e3b766;
    --focus: 0 0 0 3px rgba(125, 211, 174, 0.35);
    --shadow: 0 4px 8px rgb(0 0 0 / 0.2), 0 24px 64px -20px rgb(0 0 0 / 0.5);
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.6 var(--sans);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  text-rendering: optimizeLegibility;
}
@media (min-width: 900px) { body { font-size: 18px; } }
main { flex: 1; display: block; width: 100%; }
img { max-width: 100%; height: auto; }

h1, h2, h3 { font-family: var(--serif); font-weight: 600; color: var(--ink); line-height: 1.2; margin: 0; text-wrap: balance; }
h1 { font-size: clamp(2rem, 4.6vw, 2.9rem); letter-spacing: -0.01em; }
h2 { font-size: clamp(1.55rem, 3vw, 2.05rem); margin-bottom: 12px; }
h3 { font-size: 1.2rem; margin-bottom: 6px; }
p { margin: 0 0 1em; }

a { color: var(--accent); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: var(--accent-hover); text-decoration-thickness: 2px; }
a:focus-visible, summary:focus-visible, .button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  box-shadow: var(--focus);
  border-radius: var(--r-s);
}

code, kbd {
  font: 0.86em var(--mono);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 0.05em 0.35em;
  overflow-wrap: anywhere;
}
kbd { white-space: nowrap; }

.skip {
  position: absolute; left: 12px; top: -64px; z-index: 20;
  background: var(--accent); color: var(--on-accent);
  padding: 8px 16px; border-radius: var(--r-s); text-decoration: none; font-weight: 600;
}
.skip:focus { top: 12px; }

/* ---- header ---------------------------------------------------------------- */
.bar {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px 24px;
  padding: 16px 24px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-family: var(--serif); font-weight: 600; font-size: 1.15rem; }
.brand:hover { color: var(--ink); }
.brand img { display: block; border-radius: 6px; }
.beta {
  display: inline-block; font: 600 0.7rem/1.5 var(--sans); letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--ink-muted); border: 1px solid var(--line-strong); border-radius: 4px; padding: 0 6px; vertical-align: middle;
}
.navlist { display: flex; flex-wrap: wrap; align-items: center; gap: 4px 24px; list-style: none; margin: 0; padding: 0; }
.navlist a { color: var(--ink); text-decoration: none; padding: 6px 0; font-size: 0.95rem; }
.navlist a:hover { color: var(--accent); text-decoration: underline; }
.navlist .button { color: var(--on-accent); padding: 7px 16px; }
.navlist .button:hover { color: var(--on-accent); text-decoration: none; }

/* ---- buttons ---------------------------------------------------------------- */
.button {
  display: inline-block; background: var(--accent); color: var(--on-accent);
  padding: 11px 22px; border: 1px solid var(--accent); border-radius: var(--r-s);
  font: 600 1rem/1.3 var(--sans); text-decoration: none;
  transition: background-color var(--ease), border-color var(--ease), box-shadow var(--ease), transform var(--ease);
}
.button:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--on-accent); text-decoration: none; box-shadow: 0 4px 12px color-mix(in srgb, var(--accent) 20%, transparent); }
.button.ghost { background: transparent; color: var(--ink); border-color: var(--line-strong); }
.button.ghost:hover { background: var(--surface-2); color: var(--ink); }
@media (prefers-reduced-motion: no-preference) {
  .button:hover { transform: translateY(-1px); }
  .button:active { transform: translateY(1px); box-shadow: none; }
}
.cta { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin: 0; }

/* ---- layout ---------------------------------------------------------------- */
.wrap { width: 100%; max-width: 68rem; margin: 0 auto; padding: 64px 24px; }
.band { background: var(--surface-2); border-block: 1px solid var(--line); }
.band > .wrap { padding-block: 64px; }
.lede { font-size: 1.15rem; color: var(--ink-muted); max-width: 38rem; }
.sub { color: var(--ink-muted); max-width: 40rem; margin: 0 0 32px; }
.note { color: var(--ink-muted); font-size: 0.95rem; }

/* ---- prose (help, legal) ---------------------------------------------------- */
.prose { max-width: 68ch; margin: 0 auto; padding: 48px 24px 80px; }
.prose h1 { margin-bottom: 8px; }
.prose h2 { margin: 48px 0 12px; padding-top: 24px; border-top: 1px solid var(--line); font-size: 1.55rem; }
.prose h3 { margin: 28px 0 6px; font-size: 1.15rem; }
.prose ul, .prose ol { padding-left: 1.3em; margin: 0 0 1em; }
.prose li { margin-bottom: 0.4em; }
.prose li::marker { color: var(--ink-muted); }
.prose .sub, .prose .lede { max-width: none; }
.crumbs { font-size: 0.92rem; color: var(--ink-muted); margin: 0 0 24px; }
.updated { color: var(--ink-muted); font-size: 0.95rem; margin: 8px 0 24px; }
.summary {
  background: var(--surface); border: 1px solid var(--line); border-left: 3px solid var(--accent);
  border-radius: var(--r-s); padding: 20px 24px; margin: 0 0 32px;
}
.summary h2 { all: unset; display: block; font: 600 1.05rem var(--serif); margin-bottom: 6px; }
.summary p, .summary ul { margin-bottom: 0.5em; }
.summary > :last-child { margin-bottom: 0; }
.toc { background: var(--surface-2); border-radius: var(--r-s); padding: 16px 20px 8px; margin: 0 0 32px; }
.toc h2 { all: unset; display: block; font: 600 0.8rem var(--sans); letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-muted); margin-bottom: 8px; }
.toc ol { columns: 2 16rem; column-gap: 32px; padding-left: 1.4em; margin: 0 0 8px; font-size: 0.95rem; }
.toc li { margin-bottom: 4px; break-inside: avoid; }
.placeholder { background: var(--accent-soft); border-radius: 4px; padding: 0 0.3em; font-family: var(--mono); font-size: 0.88em; overflow-wrap: anywhere; }
.table-wrap { overflow-x: auto; margin: 0 0 1.2em; }
table { border-collapse: collapse; width: 100%; font-size: 0.93rem; line-height: 1.45; }
th, td { text-align: left; vertical-align: top; padding: 10px 12px; border-bottom: 1px solid var(--line); }
th { font-weight: 600; background: var(--surface-2); border-top: 1px solid var(--line); }
caption { text-align: left; color: var(--ink-muted); font-size: 0.9rem; padding: 0 0 8px; caption-side: top; }

.keys { margin: 0 0 24px; }
.keys div { display: grid; grid-template-columns: minmax(10rem, 16rem) 1fr; gap: 8px 16px; padding: 10px 0; border-top: 1px solid var(--line); }
.keys dt, .keys dd { margin: 0; }
.cards-list { list-style: none; padding: 0; margin: 24px 0 0; display: grid; gap: 12px; }
.cards-list li { margin: 0; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-m); padding: 16px 20px; }
.cards-list li:focus-within { border-color: var(--accent); }
.cards-list h2 { all: unset; display: block; font: 600 1.2rem var(--serif); margin-bottom: 4px; }
.cards-list p { margin: 0; color: var(--ink-muted); }

.faq details { border-top: 1px solid var(--line); padding: 14px 0; }
.faq details[open] { border-top-color: var(--accent); }
.faq summary { transition: color var(--ease); }
.faq summary:hover { color: var(--accent); }
.faq details:last-child { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; font-weight: 600; padding: 2px 0; list-style-position: outside; }
.faq summary::marker { color: var(--ink-muted); }
.faq p { margin: 10px 0 2px; color: var(--ink-muted); max-width: 62ch; }

/* ---- footer ---------------------------------------------------------------- */
.foot { border-top: 1px solid var(--line); background: var(--surface-2); color: var(--ink-muted); font-size: 0.93rem; }
.foot__in { max-width: 68rem; margin: 0 auto; padding: 32px 24px; display: grid; grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr)); gap: 24px 32px; }
.foot h2 { font: 600 0.78rem var(--sans); letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-muted); margin: 0 0 8px; }
.foot ul { list-style: none; margin: 0; padding: 0; }
.foot li { margin-bottom: 4px; }
.foot a { color: var(--ink); }
.foot a:hover { color: var(--accent); }
.foot p { margin: 0 0 6px; }
.foot__brand { font: 600 1.1rem var(--serif); color: var(--ink); margin-bottom: 6px; }

@media (max-width: 560px) {
  .bar { padding: 12px 16px; }
  .hide-small { display: none; }
  .wrap { padding: 40px 16px; }
  .band > .wrap { padding-block: 40px; }
  .prose { padding: 32px 16px 56px; }
  .foot__in { padding: 24px 16px; }
  .keys div { grid-template-columns: 1fr; gap: 2px; }
}