/* ==========================================================================
   LabRequirements.com — design system
   Identity: "clinical precision" — graphite chrome, porcelain surfaces,
   signal-amber accents, monospaced specimen labels. No external fonts,
   no frameworks, no shadows. Mobile-first.
   ========================================================================== */

:root {
  /* Surfaces */
  --chrome:        #17252F;
  --chrome-deep:   #0D181F;
  --chrome-soft:   #223642;
  --paper:         #FFFFFF;
  --porcelain:     #F1F4F7;
  --porcelain-2:   #E8EEF3;

  /* Text */
  --ink:           #132029;
  --ink-soft:      #3C4E5B;
  --muted:         #5A6E7E;
  --on-dark:       #EAF0F5;
  --on-dark-soft:  #AFC1CE;

  /* Lines */
  --line:          #D7E0E8;
  --line-strong:   #C2CFDA;

  /* Accents */
  --amber:         #E4A11B;
  --amber-ink:     #6E4C00;
  --amber-tint:    #FBF0D6;
  --blue:          #0C5C9E;
  --blue-dark:     #08487B;
  --green:         #1F7A5A;
  --red:           #B4342A;

  /* Shape & type */
  --radius:        10px;
  --radius-sm:     6px;
  --maxw:          1120px;
  --font-sans:     -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono:     ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}

/* --------------------------------------------------------------- reset */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--porcelain);
  -webkit-font-smoothing: antialiased;
}
img, svg { max-width: 100%; height: auto; }
a { color: var(--blue); text-underline-offset: 2px; }
a:hover { color: var(--blue-dark); }
h1, h2, h3, h4 { line-height: 1.2; color: var(--ink); margin: 0 0 .5em; font-weight: 700; letter-spacing: -.01em; }
p { margin: 0 0 1em; }
ul, ol { margin: 0 0 1em; padding-left: 1.25em; }
:focus-visible { outline: 3px solid var(--amber); outline-offset: 2px; border-radius: 3px; }
:target { scroll-margin-top: 90px; }

.visually-hidden {
  position: absolute !important; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap; border: 0;
}
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 1000;
  background: var(--amber); color: var(--chrome-deep);
  padding: .6rem 1rem; font-weight: 700; border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus { left: 0; }

/* --------------------------------------------------------------- layout */
.main { display: block; }
.section {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 2rem 1rem;
}
.section__head { max-width: 62ch; margin-bottom: 1.25rem; }
.section__title { font-size: 1.4rem; margin-bottom: .35rem; }
.section__lead { color: var(--ink-soft); margin: 0; }
.section__more { margin-top: 1.25rem; }
.section--prose { max-width: 760px; }
.section--faq { max-width: 760px; }
.section--citations { max-width: 760px; }

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--amber-ink);
  margin: 0 0 .5rem;
}

/* --------------------------------------------------------------- chrome */
.topbar {
  background: var(--chrome-deep);
  color: var(--on-dark-soft);
  font-size: .78rem;
  font-family: var(--font-mono);
  letter-spacing: .02em;
}
.topbar__inner {
  max-width: var(--maxw); margin: 0 auto;
  padding: .45rem 1rem;
  display: flex; gap: 1rem; justify-content: space-between; flex-wrap: wrap;
}
.topbar__item--right { color: var(--on-dark); }

.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}
.site-header__inner {
  max-width: var(--maxw); margin: 0 auto;
  padding: .7rem 1rem;
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
  justify-content: space-between;
}
.brand { display: inline-flex; align-items: center; gap: .6rem; text-decoration: none; color: var(--ink); }
.brand__mark { display: inline-flex; }
.brand__mail { display: inline-flex; } /* legacy guard */
.brand__text { display: flex; flex-direction: column; line-height: 1.1; }
.brand__name { font-weight: 800; font-size: 1.1rem; letter-spacing: -.02em; }
.brand__tag {
  font-family: var(--font-mono); font-size: .68rem;
  color: var(--muted); letter-spacing: .04em; text-transform: uppercase;
}

.nav { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.nav__list { display: flex; align-items: center; gap: .25rem; list-style: none; margin: 0; padding: 0; }
.nav__link {
  display: inline-block; padding: .5rem .7rem; border-radius: var(--radius-sm);
  color: var(--ink-soft); text-decoration: none; font-weight: 600; font-size: .95rem;
}
.nav__link:hover { background: var(--porcelain); color: var(--ink); }
.nav__link.is-active { color: var(--amber-ink); background: var(--amber-tint); }
.nav__toggle {
  display: none;
  font: inherit; font-weight: 700;
  background: var(--paper); color: var(--ink);
  border: 1px solid var(--line-strong); border-radius: var(--radius-sm);
  padding: .45rem .8rem; cursor: pointer;
}

/* --------------------------------------------------------------- buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .4rem;
  font: inherit; font-weight: 700; line-height: 1.2;
  padding: .7rem 1.1rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  text-decoration: none; cursor: pointer;
  transition: background-color .15s ease, color .15s ease, border-color .15s ease;
}
.btn--primary { background: var(--chrome); color: var(--on-dark); }
.btn--primary:hover { background: var(--chrome-soft); color: #fff; }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line-strong); }
.btn--ghost:hover { background: var(--porcelain-2); color: var(--ink); }
.btn--sm { padding: .45rem .8rem; font-size: .9rem; }
.btn--lg { padding: .85rem 1.35rem; font-size: 1.02rem; }

/* --------------------------------------------------------------- breadcrumbs */
.breadcrumbs { max-width: var(--maxw); margin: 0 auto; padding: .9rem 1rem 0; }
.breadcrumbs__list { display: flex; flex-wrap: wrap; align-items: center; gap: .35rem; list-style: none; margin: 0; padding: 0; font-size: .85rem; }
.breadcrumbs__link { color: var(--muted); text-decoration: none; }
.breadcrumbs__link:hover { color: var(--ink); text-decoration: underline; }
.breadcrumbs__current { color: var(--ink); font-weight: 600; }
.breadcrumbs__sep { color: var(--line-strong); margin-left: .35rem; }

/* --------------------------------------------------------------- hero */
.hero {
  background:
    linear-gradient(180deg, var(--chrome) 0%, var(--chrome-deep) 100%);
  color: var(--on-dark);
}
.hero__inner { max-width: var(--maxw); margin: 0 auto; padding: 2.75rem 1rem 2.5rem; }
.hero__eyebrow {
  font-family: var(--font-mono); font-size: .75rem; letter-spacing: .14em;
  text-transform: uppercase; color: var(--amber); margin: 0 0 .8rem;
}
.hero__title { color: #fff; font-size: clamp(1.75rem, 5vw, 2.6rem); margin: 0 0 .75rem; max-width: 20ch; }
.hero__lead { color: var(--on-dark-soft); font-size: 1.05rem; max-width: 60ch; margin: 0 0 1.5rem; }
.hero__actions { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 1.25rem; }
.hero__stats {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: .5rem;
  margin-top: 2rem; border-top: 1px solid rgba(255,255,255,.12); padding-top: 1.25rem;
}
.stat { display: flex; flex-direction: column; }
.stat__num { font-size: 1.5rem; font-weight: 800; color: #fff; font-variant-numeric: tabular-nums; }
.stat__label { font-family: var(--font-mono); font-size: .72rem; text-transform: uppercase; letter-spacing: .06em; color: var(--on-dark-soft); }

/* --------------------------------------------------------------- search */
.search {
  display: flex; flex-wrap: wrap; gap: .5rem;
  background: var(--paper); padding: .5rem; border-radius: var(--radius);
  border: 1px solid var(--line-strong);
}
.search__input {
  flex: 1 1 16rem; min-width: 0;
  font: inherit; padding: .65rem .8rem;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: var(--paper); color: var(--ink);
}
.search__input::placeholder { color: var(--muted); }

/* --------------------------------------------------------------- steps */
.steps { list-style: none; margin: 0; padding: 0; display: grid; gap: 1rem; }
.step { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.25rem; }
.step__num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 2rem; height: 2rem; border-radius: 50%;
  background: var(--amber-tint); color: var(--amber-ink);
  font-family: var(--font-mono); font-weight: 700; margin-bottom: .6rem;
}
.step__title { font-size: 1.1rem; margin: 0 0 .3rem; }
.step__text { color: var(--ink-soft); margin: 0; }

/* --------------------------------------------------------------- grid */
.grid { display: grid; gap: 1rem; grid-template-columns: 1fr; }

/* --------------------------------------------------------------- cards */
.card {
  position: relative; display: flex; flex-direction: column;
  background: var(--paper); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 1.1rem 1.1rem 1rem;
  text-decoration: none; color: var(--ink);
  transition: border-color .15s ease, transform .15s ease;
}
.card:hover { border-color: var(--chrome); transform: translateY(-2px); }
.card__accent {
  position: absolute; left: 0; top: 0; bottom: 0; width: 4px;
  background: var(--amber); border-radius: var(--radius) 0 0 var(--radius);
}
.card__title { font-weight: 700; font-size: 1.06rem; display: block; margin-bottom: .4rem; padding-left: .35rem; }
.card__meta { display: flex; flex-wrap: wrap; gap: .4rem; margin-bottom: .5rem; padding-left: .35rem; }
.card__body { color: var(--ink-soft); font-size: .92rem; display: block; margin-bottom: .75rem; padding-left: .35rem; }
.card__link { margin-top: auto; color: var(--blue); font-weight: 700; font-size: .92rem; padding-left: .35rem; }
.card:hover .card__link { color: var(--blue-dark); }
.chip {
  display: inline-block; font-family: var(--font-mono); font-size: .7rem;
  letter-spacing: .03em; text-transform: uppercase;
  background: var(--porcelain-2); color: var(--ink-soft);
  padding: .2rem .5rem; border-radius: 999px;
}
.chip--time { background: #E2EEF7; color: #2C4A61; }
.chip--price { background: #E6F1EB; color: #1F5A41; }

/* --------------------------------------------------------------- requirements (centerpiece) */
.reqs {
  max-width: var(--maxw);
  margin: 2rem auto;
  background: var(--paper);
  border: 1px solid var(--line-strong);
  border-top: 4px solid var(--amber);
  border-radius: var(--radius);
  padding: 1.5rem 1.25rem;
}
.reqs__head { margin-bottom: 1rem; }
.reqs__tag {
  display: inline-flex; align-items: center; gap: .5rem;
  font-family: var(--font-mono); font-size: .75rem; font-weight: 700;
  letter-spacing: .12em; text-transform: uppercase; color: var(--amber-ink);
  margin: 0 0 .6rem;
}
.reqs__dot { width: .6rem; height: .6rem; border-radius: 50%; background: var(--amber); display: inline-block; }
.reqs__intro p { margin: 0; color: var(--ink-soft); max-width: 70ch; }
.reqs__list { margin: 0; border-top: 1px solid var(--line); }
.reqs__row { display: grid; grid-template-columns: 1fr; gap: .15rem; padding: .85rem 0; border-bottom: 1px solid var(--line); }
.reqs__label {
  font-family: var(--font-mono); font-size: .72rem; letter-spacing: .08em;
  text-transform: uppercase; color: var(--muted);
}
.reqs__value { margin: 0; font-weight: 600; color: var(--ink); }
.reqs__prep { margin-top: 1.25rem; background: var(--amber-tint); border-radius: var(--radius-sm); padding: 1rem 1.1rem; }
.reqs__prep-title { font-size: .95rem; margin: 0 0 .5rem; color: var(--amber-ink); }
.reqs__bullets { list-style: none; margin: 0; padding: 0; display: grid; gap: .4rem; }
.reqs__bullets li { position: relative; padding-left: 1.5rem; color: var(--ink); }
.reqs__bullets li::before {
  content: "\2713"; position: absolute; left: 0; top: 0;
  color: var(--amber-ink); font-weight: 800;
}
.reqs__note { margin: 1rem 0 0; font-size: .8rem; color: var(--muted); border-top: 1px dashed var(--line-strong); padding-top: .75rem; }

/* --------------------------------------------------------------- CTA */
.cta { max-width: var(--maxw); margin: 2rem auto; padding: 0 1rem; }
.cta__inner {
  border-radius: var(--radius); padding: 1.5rem 1.25rem;
  border: 1px solid var(--line-strong); background: var(--paper);
}
.cta__title { font-size: 1.25rem; margin: 0 0 .5rem; }
.cta__text { color: var(--ink-soft); margin: 0 0 1rem; max-width: 68ch; }
.cta__actions { display: flex; flex-wrap: wrap; gap: .75rem; }
.cta__note { margin: 1rem 0 0; font-size: .78rem; color: var(--muted); max-width: 80ch; }
.cta--banner .cta__inner { background: linear-gradient(180deg, var(--chrome) 0%, var(--chrome-deep) 100%); border-color: var(--chrome-deep); }
.cta--banner .cta__title { color: #fff; }
.cta--banner .cta__text { color: var(--on-dark-soft); }
.cta--banner .cta__note { color: var(--on-dark-soft); }
.cta--banner .btn--primary { background: var(--amber); color: var(--chrome-deep); }
.cta--banner .btn--primary:hover { background: #F2B232; }
.cta--banner .btn--ghost { color: var(--on-dark); border-color: rgba(255,255,255,.35); }
.cta--banner .btn--ghost:hover { background: rgba(255,255,255,.08); color: #fff; }

/* --------------------------------------------------------------- page head */
.page-head { max-width: var(--maxw); margin: 0 auto; padding: 2rem 1rem 0; }
.page-head__title { font-size: clamp(1.5rem, 4.5vw, 2.1rem); margin: 0 0 .6rem; }
.page-head__lead { color: var(--ink-soft); max-width: 68ch; margin: 0; }

/* --------------------------------------------------------------- test hero + facts */
.test-hero { max-width: var(--maxw); margin: 0 auto; padding: 2rem 1rem .5rem; }
.test-hero__title { font-size: clamp(1.5rem, 4.5vw, 2.1rem); margin: 0 0 .6rem; }
.test-hero__lead { color: var(--ink-soft); max-width: 68ch; }
.test-facts {
  display: grid; grid-template-columns: 1fr; gap: .5rem 1rem;
  margin: 1.25rem 0; padding: 1rem 1.1rem;
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
}
.fact { display: flex; flex-direction: column; }
.fact__label {
  font-family: var(--font-mono); font-size: .7rem; letter-spacing: .08em;
  text-transform: uppercase; color: var(--muted);
}
.fact__value { font-weight: 600; }

/* --------------------------------------------------------------- index lists */
.test-index-wrap { margin-top: 1.5rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); }
.test-index__summary { cursor: pointer; font-weight: 700; padding: .9rem 1.1rem; }
.test-index { columns: 1; column-gap: 1.5rem; list-style: none; margin: 0; padding: .25rem 1.1rem 1rem; }
.test-index li { break-inside: avoid; margin: 0 0 .35rem; }
.toc { margin: 1rem 0; }
.toc__list { display: flex; flex-wrap: wrap; gap: .35rem; list-style: none; margin: 0; padding: 0; }
.toc__link {
  display: inline-block; min-width: 2rem; text-align: center;
  padding: .25rem .5rem; border: 1px solid var(--line); border-radius: var(--radius-sm);
  text-decoration: none; font-family: var(--font-mono); font-weight: 600; color: var(--ink-soft);
}
.toc__link:hover { background: var(--amber-tint); color: var(--amber-ink); border-color: var(--amber); }
.letter-group { margin-top: 1.75rem; }

/* --------------------------------------------------------------- prose */
.prose { max-width: 72ch; }
.prose h2 { font-size: 1.3rem; margin-top: 1.75rem; padding-top: .25rem; }
.prose h3 { font-size: 1.1rem; margin-top: 1.4rem; }
.prose ul, .prose ol { padding-left: 1.3rem; }
.prose li { margin-bottom: .35rem; }
.prose strong { color: var(--ink); }
.prose a { text-decoration: underline; }

/* --------------------------------------------------------------- FAQ */
.faq { border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); overflow: hidden; }
.faq__item { border-bottom: 1px solid var(--line); }
.faq__item:last-child { border-bottom: 0; }
.faq__q {
  cursor: pointer; list-style: none; padding: 1rem 1.1rem;
  font-weight: 700; position: relative; padding-right: 2.5rem;
}
.faq__q::-webkit-details-marker { display: none; }
.faq__q::after {
  content: "+"; position: absolute; right: 1.1rem; top: 50%; transform: translateY(-50%);
  font-family: var(--font-mono); color: var(--amber-ink); font-weight: 700;
}
.faq__item[open] .faq__q::after { content: "\2212"; }
.faq__a { padding: 0 1.1rem 1rem; color: var(--ink-soft); }
.faq__a p:last-child { margin-bottom: 0; }

/* --------------------------------------------------------------- article / guides */
.article { max-width: 760px; margin: 0 auto; padding: 2rem 1rem 0; }
.article__head { margin-bottom: 1.5rem; }
.article__title { font-size: clamp(1.6rem, 4.5vw, 2.2rem); margin: 0 0 .6rem; }
.article__lead { color: var(--ink-soft); font-size: 1.05rem; }
.article__meta { font-family: var(--font-mono); font-size: .75rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); }
.keypoints { background: var(--porcelain-2); border-radius: var(--radius); padding: 1.1rem 1.25rem; margin: 0 0 1.5rem; }
.keypoints__title { font-size: 1rem; margin: 0 0 .5rem; }
.keypoints__list { margin: 0; padding-left: 1.2rem; }
.keypoints__list li { margin-bottom: .3rem; }
.citations { padding-left: 1.25rem; }
.citations li { margin-bottom: .4rem; font-size: .9rem; }

/* --------------------------------------------------------------- footer */
.site-footer { background: var(--chrome-deep); color: var(--on-dark-soft); margin-top: 3rem; }
.footer__grid {
  max-width: var(--maxw); margin: 0 auto; padding: 2.5rem 1rem 1.5rem;
  display: grid; grid-template-columns: 1fr; gap: 1.75rem;
}
.footer__brand { display: block; color: #fff; font-weight: 800; font-size: 1.15rem; margin-bottom: .6rem; }
.footer__blurb { font-size: .85rem; color: var(--on-dark-soft); max-width: 46ch; }
.footer__title { font-family: var(--font-mono); font-size: .75rem; letter-spacing: .1em; text-transform: uppercase; color: var(--amber); margin: 0 0 .6rem; }
.footer__list { list-style: none; margin: 0; padding: 0; }
.footer__list li { margin-bottom: .35rem; }
.footer__link { color: var(--on-dark); text-decoration: none; font-size: .9rem; }
.footer__link:hover { color: #fff; text-decoration: underline; }
.footer__bottom { border-top: 1px solid rgba(255,255,255,.12); }
.footer__bottom { max-width: var(--maxw); margin: 0 auto; padding: 1.1rem 1rem 2rem; }
.footer__legal { font-size: .75rem; color: var(--muted); margin: 0 0 .4rem; }

/* --------------------------------------------------------------- responsive */
@media (min-width: 560px) {
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .test-facts { grid-template-columns: repeat(2, 1fr); }
  .reqs__row { grid-template-columns: 11rem 1fr; align-items: baseline; gap: 1rem; }
  .test-index { columns: 2; }
}
@media (min-width: 860px) {
  .section { padding: 3rem 1.5rem; }
  .hero__inner { padding: 4rem 1.5rem 3.5rem; }
  .grid { gap: 1.25rem; }
  .grid--3 { grid-template-columns: repeat(3, 1fr); }
  .grid--4 { grid-template-columns: repeat(4, 1fr); }
  .steps { grid-template-columns: repeat(3, 1fr); }
  .test-facts { grid-template-columns: repeat(4, 1fr); }
  .footer__grid { grid-template-columns: 2fr 1fr 1fr 1fr; }
  .reqs { padding: 2rem 2rem 1.75rem; }
  .test-index { columns: 3; }
}

/* Mobile navigation */
@media (max-width: 719px) {
  .nav__toggle { display: inline-block; }
  .nav {
    display: none;
    flex-basis: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: .25rem;
  }
  .nav.is-open { display: flex; }
  .nav__list { flex-direction: column; align-items: stretch; }
  .nav__link { padding: .7rem .7rem; }
  .nav .btn { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

/* --------------------------------------------------------------- explicit coverage */
.nav__item { list-style: none; }
.breadcrumbs__item { list-style: none; display: flex; align-items: center; }
.topbar__item { white-space: nowrap; }
.footer__col { min-width: 0; }
.footer__col--brand { max-width: 46ch; }
.hero--home { /* base hero carries the treatment */ }
.page-head--404 { padding-bottom: .5rem; }
.page-head--404 .hero__actions { margin-top: 1.25rem; }
.test-index--city { columns: 1; }

/* Card accents by type — keeps the system legible at a glance. */
.card--test .card__accent   { background: var(--amber); }
.card--state .card__accent  { background: var(--chrome); }
.card--guide .card__accent  { background: var(--blue); }
.card--city .card__accent   { background: var(--green); }