:root {
  --ink: #16202b;
  --muted: #5a6b7c;
  --line: #dbe3ea;
  --brand: #0f6bc4;
  --brand-dark: #23395e;
  --brand-darkest: #101d33;
  --accent: #e2a53d;
  --red: #bb262c;
  --bg-soft: #f4f7fa;
  --max: 62rem;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font: 1.125rem/1.7 system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: #fff;
}

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }

a { color: var(--brand); }
a:hover { color: var(--brand-dark); }

/* Header */
.site-header { background: var(--brand-darkest); color: #fff; }
.site-header .wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 1rem;
  padding-top: 0.9rem;
  padding-bottom: 0.9rem;
}
.brand {
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.3rem;
  margin-right: auto;
}
.brand:hover { color: #fff; }
.brand-sponsor { font-size: 0.85rem; color: #b9c6d8; }
.brand-sponsor a { color: #fff; }

/* Menu bar: each section is a <details> so the drop-downs work without JavaScript */
.site-nav { background: var(--brand-dark); border-bottom: 4px solid var(--accent); }
.site-nav > .wrap { display: flex; flex-wrap: wrap; align-items: stretch; max-width: 68rem; padding: 0 0.7rem; }
.site-nav a, .site-nav summary {
  display: block;
  color: #e8f1f8;
  text-decoration: none;
  font-size: 0.9rem;
  padding: 0.7rem 0.5rem;
  white-space: nowrap;
  border-bottom: 3px solid transparent;
}
.site-nav > .wrap > a:last-child { margin-left: auto; }
.site-nav > .wrap > a:hover,
.site-nav summary:hover,
.site-nav summary.here {
  color: #fff;
  background: var(--brand-darkest);
  border-bottom-color: var(--accent);
}

.menu { position: relative; }
.menu summary { cursor: pointer; list-style: none; white-space: nowrap; }
.menu summary::-webkit-details-marker { display: none; }
.menu summary::after {
  content: "";
  display: inline-block;
  margin-left: 0.35rem;
  border: 0.3rem solid transparent;
  border-top-color: currentColor;
  vertical-align: 0.05em;
}
.menu[open] summary { color: #fff; background: var(--brand-darkest); }
.menu[open] > ul {
  position: absolute;
  z-index: 20;
  top: 100%;
  left: 0;
  min-width: 15rem;
  margin: 0;
  padding: 0.35rem 0;
  list-style: none;
  background: #fff;
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  border-radius: 0 0 6px 6px;
  box-shadow: 0 8px 20px #0b2a4022;
}
.menu ul a {
  color: var(--brand-dark);
  font-size: 0.95rem;
  padding: 0.5rem 1rem;
  border-bottom: 0;
  font-weight: 600;
}
.menu ul a:hover, .menu ul a[aria-current="page"] {
  background: var(--bg-soft);
  color: var(--brand-dark);
  border-bottom: 0;
}
.menu ul a[aria-current="page"] { box-shadow: inset 4px 0 0 var(--accent); }

/* Hero */
.hero {
  background: linear-gradient(180deg, var(--brand-dark) 0%, var(--brand-darkest) 100%);
  color: #fff;
  padding: 3.5rem 0;
}
.hero h1 { font-size: 2.6rem; line-height: 1.15; margin: 0 0 1rem; }
.hero p { font-size: 1.3rem; max-width: 44rem; margin: 0 0 1.5rem; color: #dbeaf5; }

.btn {
  display: inline-block;
  background: var(--accent);
  color: #22303c;
  font-weight: 700;
  text-decoration: none;
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  margin: 0 0.5rem 0.5rem 0;
}
.btn:hover { background: #f0b95c; color: #22303c; }
.btn-ghost { background: transparent; color: #fff; border: 2px solid #ffffff88; }
.btn-ghost:hover { background: #ffffff1a; color: #fff; }

/* Sections */
main { padding: 2.5rem 0 3.5rem; }
article h1 { font-size: 2.1rem; margin: 0 0 0.75rem; line-height: 1.2; }
h2 { font-size: 1.9rem; margin: 2.5rem 0 0.75rem; line-height: 1.2; }
h3 { font-size: 1.3rem; margin: 1.75rem 0 0.5rem; }
p, li { max-width: 46rem; }
.lead { font-size: 1.25rem; color: var(--muted); }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
}
.card { border: 1px solid var(--line); border-radius: 6px; padding: 1.25rem; background: #fff; }
.card h3 { margin-top: 0; }
.card p { font-size: 1rem; color: var(--muted); margin-bottom: 0; }
.card a { font-weight: 600; }

.callout {
  background: var(--bg-soft);
  border-left: 5px solid var(--brand);
  border-radius: 0 6px 6px 0;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
}
.callout h3 { margin-top: 0; }
.callout p:last-child { margin-bottom: 0; }

.steps { counter-reset: step; list-style: none; padding: 0; }
.steps > li { counter-increment: step; position: relative; padding-left: 3.25rem; margin-bottom: 1.75rem; }
.steps > li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 50%;
  background: var(--brand-dark);
  color: #fff;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}
.steps h3 { margin: 0 0 0.35rem; }

.table-scroll { overflow-x: auto; margin: 1.25rem 0; }
table { border-collapse: collapse; width: 100%; max-width: 46rem; margin: 1.25rem 0; }
.table-scroll table { max-width: none; min-width: 34rem; margin: 0; }
th, td { border: 1px solid var(--line); padding: 0.6rem 0.8rem; text-align: left; font-size: 1rem; vertical-align: top; }
th { background: var(--bg-soft); }

.faq details { border-bottom: 1px solid var(--line); padding: 0.9rem 0; }
.faq summary { font-weight: 600; cursor: pointer; font-size: 1.1rem; }
.faq p { margin-bottom: 0; }

/* Glossary */
.glossary dt { font-weight: 700; color: var(--brand-dark); margin-top: 1.1rem; }
.glossary dd { margin: 0.2rem 0 0; max-width: 46rem; }

/* Two-column page layout with an "In this section" sidebar */
.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 18rem;
  gap: 2.5rem;
  align-items: start;
}
.layout > article > h2:first-child,
.layout > article > h1:first-child { margin-top: 0; }

.sidebar { position: sticky; top: 1.5rem; }
.section-nav {
  border: 1px solid var(--line);
  border-top: 4px solid var(--brand-dark);
  border-radius: 0 0 6px 6px;
  background: var(--bg-soft);
  padding: 1.1rem 1.25rem;
  margin-bottom: 1.5rem;
}
.section-nav h2 {
  font-size: 1.05rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  margin: 0 0 0.75rem;
}
.section-nav ul { list-style: none; margin: 0; padding: 0; }
.section-nav li { border-top: 1px solid var(--line); }
.section-nav li:first-child { border-top: 0; }
.section-nav a { display: block; padding: 0.55rem 0; font-size: 1rem; text-decoration: none; font-weight: 600; }
.section-nav a:hover { text-decoration: underline; }
.section-nav a[aria-current="page"] {
  color: var(--ink);
  border-left: 4px solid var(--accent);
  padding-left: 0.6rem;
  margin-left: -0.6rem;
}

/* On narrow screens the section box is the only navigation, so it moves above the page text. */
@media (max-width: 55rem) {
  .layout { display: flex; flex-direction: column; gap: 1.5rem; }
  .sidebar { position: static; order: -1; }
}

/* Footer */
.site-footer {
  background: var(--bg-soft);
  border-top: 1px solid var(--line);
  padding: 2.5rem 0;
  font-size: 1rem;
  color: var(--muted);
}
.site-footer .wrap { display: grid; grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr)); gap: 1.5rem; }
.site-footer h4 { margin: 0 0 0.5rem; color: var(--ink); font-size: 1rem; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: 0.35rem; }
.sponsor strong { color: var(--ink); }

/* A single row of onward links across the bottom of the footer */
.site-footer .footer-links {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.6rem 1.5rem;
  margin-top: 2rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  font-size: 0.95rem;
}
.site-footer .footer-links h4 { flex-basis: 100%; margin: 0; }

.skip { position: absolute; left: -9999px; }
.skip:focus { left: 1rem; top: 0.5rem; background: #fff; padding: 0.5rem 1rem; z-index: 10; }

/* Narrow screens: the menu bar stacks and the drop-downs open in flow rather than floating. */
@media (max-width: 45rem) {
  .site-nav > .wrap { display: block; padding: 0; }
  .site-nav > .wrap > a, .site-nav summary { padding: 0.7rem 1.25rem; border-bottom: 1px solid #ffffff22; }
  .menu[open] > ul {
    position: static;
    border: 0;
    border-radius: 0;
    box-shadow: none;
    background: var(--brand-darkest);
  }
  .menu ul a { color: #e8f1f8; padding-left: 2.5rem; }
  .menu ul a:hover, .menu ul a[aria-current="page"] { background: #ffffff1a; color: #fff; }
}

@media (max-width: 40rem) {
  body { font-size: 1.05rem; }
  .hero { padding: 2.5rem 0; }
  .hero h1 { font-size: 2rem; }
  .hero p { font-size: 1.15rem; }
}