/* Page CSS for the spec section's pages other than the spec itself. Colors,
   code, tables, callouts, pills, and chips come from /assets/smart-design.css;
   this file is layout and type, and takes every color from its tokens.

   - The explainers (Request and response, Kiosk check-in, Security and
     limits, Platform notes): <main class="page">.
   - The wire pages (Wire protocol, Capture inspector): <main class="wire">.
   The diagrams (inline SVG, class "xd") are styled by the shared stylesheet
   (MAINTAINING.md, "Diagrams"). */

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-relaxed);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---- The explainers ---- */
.page { max-width: 960px; margin: 0 auto; padding: 36px 24px 56px; }
.page > header { padding-bottom: 28px; border-bottom: 1px solid var(--border); }

:where(.page) :is(h1, h2, h3) {
  margin: 0;
  color: var(--fg-1);
  line-height: var(--lh-tight);
  letter-spacing: var(--tracking-tight);
  text-wrap: balance;
}
:where(.page) h1 { max-width: 820px; font-size: clamp(2.1rem, 4.4vw, 3.4rem); font-weight: 800; letter-spacing: -0.035em; }
:where(.page) h2 { margin-bottom: var(--space-3); font-size: clamp(1.55rem, 2.8vw, 2rem); font-weight: 700; letter-spacing: var(--tracking-snug); line-height: var(--lh-snug); }
:where(.page) h3 { margin: var(--space-7) 0 var(--space-2); font-size: var(--fs-lg); font-weight: 600; letter-spacing: 0; line-height: var(--lh-snug); }

:where(.page) p { max-width: 38em; margin: 0 0 var(--space-4); text-wrap: pretty; }
:where(.page) .lede { margin-top: var(--space-5); color: var(--fg-2); font-size: var(--fs-md); }
/* Callouts span the column, not just the text measure. */
:where(.page) p.smart-callout { max-width: none; }

:where(.page) a {
  color: var(--brand);
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out);
}
:where(.page) a:hover { color: var(--brand-ink); border-bottom-color: currentColor; }

/* "On this page" links under the header. */
.toc { display: flex; flex-wrap: wrap; gap: 10px 18px; padding: var(--space-4) 0; border-bottom: 1px solid var(--border); }
.toc a { color: var(--fg-2); font-size: var(--fs-sm); }

:where(.page) section { padding: var(--space-7) 0; border-bottom: 1px solid var(--border); }
:where(.page) section:last-child { border-bottom: 0; }

/* Numbered steps. */
.steps { margin: var(--space-5) 0 0; padding: 0; list-style: none; counter-reset: step; }
.steps li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 14px;
  padding: var(--space-3) 0;
  border-top: 1px solid var(--border);
}
.steps li:first-child { border-top: 0; }
.steps li::before {
  content: counter(step);
  width: 30px; height: 30px;
  display: grid; place-items: center;
  border: 1px solid var(--border-strong);
  border-radius: 50%;
  color: var(--brand);
  font-weight: 700;
  font-size: var(--fs-sm);
  background: var(--surface);
}

@media (max-width: 760px) {
  body { font-size: 15.5px; }
  .page { padding: 28px 16px 48px; }
}

/* Text pages (Security and timeouts, Platform notes): a narrower column. */
.page.narrow { max-width: 860px; }
:where(.narrow) ul { padding-left: 22px; }
:where(.narrow) li { max-width: 38em; margin: 6px 0; text-wrap: pretty; }

/* ---- The wire pages ---- */
:where(.wire) .page-head { border-bottom: 1px solid var(--border); }
:where(.wire) .wrap { max-width: 1080px; margin: 0 auto; padding: 28px; }
:where(.wire) :is(h1, h2, h3, h4) { line-height: 1.13; margin: 0; }
:where(.wire) h1 { font-size: clamp(1.6rem, 2.6vw, 2.4rem); letter-spacing: -0.02em; margin: 4px 0 0; }
:where(.wire) h2 { font-size: 1.45rem; letter-spacing: -0.005em; margin-bottom: 8px; }
:where(.wire) h3 { font-size: 1.18rem; margin-bottom: 8px; }
:where(.wire) h4 { font-size: 1rem; margin-bottom: 8px; color: var(--fg-2); text-transform: uppercase; letter-spacing: 0.04em; }
:where(.wire) p { margin: 0 0 12px; }
:where(.wire) a { color: var(--brand); }
:where(.wire) .lede { color: var(--fg-2); font-size: 1.04rem; max-width: 760px; margin-top: 14px; }
:where(.wire) section { min-width: 0; padding: 30px 0; border-bottom: 1px solid var(--border); }
:where(.wire) .small { color: var(--fg-2); font-size: 0.92rem; }
@media (max-width: 980px) {
  :where(.wire) .wrap { padding: 18px; }
}

/* ---- Requirement tags, on every page ---- */
/* A link to the rule in the spec. */
a.rid {
  display: inline-block;
  padding: 0 6px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-alt);
  color: var(--brand-ink);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  line-height: 18px;
  white-space: nowrap;
  vertical-align: 1px;
}
a.rid:hover { border-color: var(--brand); }