:root {
  --ink: #14202b;
  --muted: #51606b;
  --accent: #0b6e8f;
  --accent-dark: #084e66;
  --line: #dde5ea;
  --bg: #ffffff;
  --bg-soft: #f3f7f9;
  --warn-bg: #fff8e6;
  --warn-line: #e6c64d;
  --maxw: 60rem;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
}
.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 1.25rem; }
a { color: var(--accent); }
a:hover { color: var(--accent-dark); }
h1, h2, h3 { line-height: 1.25; color: var(--ink); }
h1 { font-size: 2rem; margin: 0 0 .5rem; }
h2 { font-size: 1.4rem; margin: 2rem 0 .75rem; }
h3 { font-size: 1.12rem; margin: 1.5rem 0 .5rem; }

.skip-link {
  position: absolute; left: -999px; top: 0; background: var(--accent);
  color: #fff; padding: .5rem 1rem; z-index: 10;
}
.skip-link:focus { left: 0; }

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  position: sticky; top: 0; z-index: 5;
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; min-height: 64px; gap: 1rem; flex-wrap: wrap; }
.brand { font-weight: 700; font-size: 1.15rem; text-decoration: none; color: var(--ink); }
.site-header nav { display: flex; gap: 1.25rem; flex-wrap: wrap; }
.site-header nav a { text-decoration: none; font-weight: 500; }

main { padding: 2rem 0 3rem; }

.hero { background: var(--bg-soft); border: 1px solid var(--line); border-radius: 14px; padding: 2rem; margin-bottom: 1.5rem; }
.hero p { color: var(--muted); font-size: 1.1rem; max-width: 44rem; }

.lede { color: var(--muted); font-size: 1.08rem; max-width: 46rem; }

.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.card { border: 1px solid var(--line); border-radius: 12px; padding: 1.25rem; background: var(--bg); }
.card h3 { margin-top: 0; }
.card a { font-weight: 600; }

.btn { display: inline-block; background: var(--accent); color: #fff; padding: .65rem 1.1rem; border-radius: 8px; text-decoration: none; font-weight: 600; }
.btn:hover { background: var(--accent-dark); color: #fff; }

table.ref-ranges { border-collapse: collapse; width: 100%; margin: 1rem 0; font-size: .95rem; }
.ref-ranges th, .ref-ranges td { border: 1px solid var(--line); padding: .55rem .7rem; text-align: left; }
.ref-ranges thead { background: var(--bg-soft); }

.callout { background: var(--warn-bg); border: 1px solid var(--warn-line); border-radius: 10px; padding: 1rem 1.15rem; margin: 1.5rem 0; }
.callout strong { display: block; margin-bottom: .25rem; }

article.news-item { border-bottom: 1px solid var(--line); padding: 1.25rem 0; }
article.news-item:last-child { border-bottom: none; }
.news-item .meta { color: var(--muted); font-size: .9rem; }

.citations { background: var(--bg-soft); border-radius: 10px; padding: 1rem 1.25rem; margin-top: 1rem; }
.citations h2, .citations h3 { margin-top: 0; }
.citations ol { margin: .5rem 0 0; padding-left: 1.25rem; }
.citations li { margin-bottom: .4rem; font-size: .92rem; word-break: break-word; }

.breadcrumb { font-size: .9rem; color: var(--muted); margin-bottom: .5rem; }
.breadcrumb a { text-decoration: none; }

.site-footer { border-top: 1px solid var(--line); background: var(--bg-soft); margin-top: 2rem; }
.site-footer .wrap { padding: 2rem 1.25rem; }
.medical-disclaimer { border-left: 4px solid var(--accent); padding-left: 1rem; }
.medical-disclaimer h2 { margin-top: 0; font-size: 1.1rem; }
.medical-disclaimer p { color: var(--muted); font-size: .92rem; max-width: 52rem; }
.footer-meta { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: .75rem; margin-top: 1.5rem; font-size: .9rem; color: var(--muted); }
.footer-meta nav { display: flex; gap: 1rem; flex-wrap: wrap; }
.footer-meta a { text-decoration: none; }

/* --- brand / nav --- */
.brand { display: inline-flex; align-items: center; gap: .5rem; }
.brand-mark { background: var(--accent); color: #fff; font-size: .72rem; font-weight: 700; letter-spacing: .04em; padding: .2rem .4rem; border-radius: 5px; }
.nav-toggle, .nav-toggle-label { display: none; }

/* --- hero actions / buttons --- */
.hero-actions { display: flex; gap: .75rem; flex-wrap: wrap; margin-top: 1.25rem; }
.btn-ghost { background: transparent; color: var(--accent); border: 1px solid var(--accent); }
.btn-ghost:hover { background: var(--bg-soft); color: var(--accent-dark); }

/* --- breadcrumb --- */
.breadcrumb { margin: 0 0 1rem; font-size: .88rem; color: var(--muted); }
.breadcrumb ol { list-style: none; display: flex; flex-wrap: wrap; gap: .4rem; margin: 0; padding: 0; }
.breadcrumb li + li::before { content: "/"; margin-right: .4rem; color: var(--line); }
.breadcrumb a { text-decoration: none; }
.breadcrumb [aria-current="page"] { color: var(--ink); font-weight: 500; }

/* --- byline (E-E-A-T) --- */
.byline { display: flex; flex-wrap: wrap; gap: .35rem 1rem; font-size: .85rem; color: var(--muted); border-bottom: 1px solid var(--line); padding-bottom: .9rem; margin: 0 0 1.5rem; }
.byline a { text-decoration: none; }

/* --- popular topics columns (home) --- */
.topic-columns { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 1.25rem 2rem; margin: 1rem 0 1.5rem; }
.topic-columns h3 { margin: 0 0 .5rem; font-size: .95rem; }
.topic-columns ul { list-style: none; margin: 0; padding: 0; }
.topic-columns li { margin-bottom: .35rem; }
.topic-columns a { text-decoration: none; }
.topic-columns a:hover { text-decoration: underline; }

/* --- table of contents --- */
.toc { background: var(--bg-soft); border: 1px solid var(--line); border-radius: 12px; padding: 1rem 1.25rem; margin: 0 0 1.75rem; }
.toc-title { margin: 0 0 .5rem; font-size: .8rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); }
.toc ul { margin: 0; padding-left: 1.1rem; columns: 2; column-gap: 2rem; }
.toc li { margin-bottom: .3rem; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }
:target { scroll-margin-top: 80px; }
@media (max-width: 600px) { .toc ul { columns: 1; } }

/* --- FAQ --- */
.faq { margin: 2rem 0; }
.faq-item { border: 1px solid var(--line); border-radius: 10px; padding: 1rem 1.15rem; margin-bottom: .75rem; background: var(--bg); }
.faq-q { margin: 0 0 .4rem; font-size: 1.05rem; }
.faq-a { color: var(--muted); }
.faq-a p { margin: 0; }

/* --- glossary --- */
.glossary dt { font-weight: 700; margin-top: 1rem; }
.glossary dd { margin: .25rem 0 0; color: var(--muted); }

/* --- related --- */
.related { background: var(--bg-soft); border-radius: 12px; padding: 1.25rem 1.5rem; margin: 2.5rem 0 0; }
.related h2 { margin-top: 0; font-size: 1.15rem; }
.related ul { columns: 2; column-gap: 2rem; margin: .5rem 0 0; padding-left: 1.1rem; }
.related li { margin-bottom: .35rem; }

/* --- footer columns --- */
.footer-columns { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1.5rem; margin: 2rem 0 1.5rem; padding: 1.5rem 0 0; border-top: 1px solid var(--line); }
.footer-columns h3 { font-size: .8rem; text-transform: uppercase; letter-spacing: .05em; color: var(--ink); margin: 0 0 .6rem; }
.footer-columns a { display: block; text-decoration: none; color: var(--muted); font-size: .9rem; margin-bottom: .35rem; }
.footer-columns a:hover { color: var(--accent); }
.disclaimer-meta { font-style: italic; }

/* --- search --- */
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.nav-search { font-weight: 600; }
.search-box input[type="search"] { width: 100%; font-size: 1.05rem; padding: .8rem 1rem; border: 1px solid var(--line); border-radius: 10px; }
.search-box input[type="search"]:focus { outline: 2px solid var(--accent); border-color: var(--accent); }
#search-status { color: var(--muted); font-size: .9rem; margin: .6rem 0 0; }
.search-results { list-style: none; padding: 0; margin: 1.25rem 0 0; }
.search-results li { border-bottom: 1px solid var(--line); padding: .9rem 0; }
.search-results li a { font-weight: 600; font-size: 1.08rem; text-decoration: none; }
.search-results .search-section { display: inline-block; margin-left: .6rem; font-size: .72rem; text-transform: uppercase; letter-spacing: .04em; color: #fff; background: var(--accent); border-radius: 4px; padding: .1rem .4rem; vertical-align: middle; }
.search-results li p { margin: .3rem 0 0; color: var(--muted); font-size: .92rem; }

@media (max-width: 700px) {
  .nav-toggle-label { display: block; cursor: pointer; padding: .5rem; }
  .nav-toggle-label span, .nav-toggle-label span::before, .nav-toggle-label span::after { display: block; width: 22px; height: 2px; background: var(--ink); position: relative; }
  .nav-toggle-label span::before, .nav-toggle-label span::after { content: ""; position: absolute; }
  .nav-toggle-label span::before { top: -7px; }
  .nav-toggle-label span::after { top: 7px; }
  .site-header nav { display: none; flex-basis: 100%; flex-direction: column; gap: .25rem; padding-bottom: .75rem; }
  .nav-toggle:checked ~ nav { display: flex; }
  .related ul { columns: 1; }
}

@media (max-width: 540px) {
  h1 { font-size: 1.6rem; }
  .hero { padding: 1.5rem; }
}