:root {
  color-scheme: light;
  --ink: #162033;
  --muted: #5e6a7d;
  --line: #d9e1ec;
  --surface: #ffffff;
  --soft: #f3f6fa;
  --accent: #c4242d;
  --accent-dark: #8e151d;
  --code: #121927;
  --code-ink: #eef3fb;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: #eef2f7;
  font-family: Inter, "Segoe UI", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
}

a { color: #174f9d; }
a:hover { color: var(--accent-dark); }

.shell {
  width: min(1080px, calc(100% - 32px));
  margin-inline: auto;
}

.site-header {
  color: #fff;
  background: #151d2c;
  border-bottom: 4px solid var(--accent);
}

.header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.back-link { color: #fff; font-weight: 700; text-decoration: none; }
.back-link:hover { color: #ffd7da; }
.header-label { color: #cdd6e5; font-size: .9rem; letter-spacing: .04em; text-transform: uppercase; }

.landing { padding-block: 54px 72px; }

.hero { max-width: 850px; margin-bottom: 32px; }
.eyebrow { margin: 0 0 8px; color: var(--accent); font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
h1 { margin: 0 0 16px; font-size: clamp(2.1rem, 5vw, 4rem); line-height: 1.08; letter-spacing: -.035em; }
.lead { margin: 0; color: var(--muted); font-size: 1.18rem; }

.notice,
.route,
.document {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: 0 12px 36px rgba(28, 39, 58, .06);
}

.notice { padding: 24px 28px; border-left: 5px solid var(--accent); }
.notice h2, .route h2 { margin-top: 0; }
.notice li + li, .route li + li { margin-top: 7px; }

.lab-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-block: 28px;
}

.lab-card {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 26px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: 0 12px 36px rgba(28, 39, 58, .05);
}

.lab-number { color: var(--accent); font-size: 2.2rem; font-weight: 900; line-height: 1; }
.lab-meta { margin: 14px 0 6px; color: var(--muted); font-size: .84rem; font-weight: 700; text-transform: uppercase; }
.lab-card h2 { margin: 0 0 10px; font-size: 1.45rem; line-height: 1.25; }
.lab-card p { margin-top: 0; }

.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin-top: auto; padding-top: 12px; }
.actions a { font-weight: 700; }
.actions .primary {
  display: inline-block;
  padding: 9px 14px;
  color: #fff;
  background: var(--accent);
  border-radius: 8px;
  text-decoration: none;
}
.actions .primary:hover { background: var(--accent-dark); }

.route { padding: 26px 30px; }

.document-page { padding-block: 42px 72px; }
.document-meta { margin-bottom: 18px; color: var(--muted); }
.document {
  padding: clamp(22px, 5vw, 56px);
  overflow-wrap: anywhere;
}

.document h1 { font-size: clamp(2rem, 5vw, 3.25rem); }
.document h2 { margin-top: 2.1em; padding-bottom: .35em; border-bottom: 1px solid var(--line); font-size: 1.6rem; line-height: 1.25; }
.document h3 { margin-top: 1.7em; font-size: 1.25rem; }
.document h4 { margin-top: 1.5em; }
.document li + li { margin-top: .35em; }
.document blockquote { margin-inline: 0; padding: 2px 18px; color: var(--muted); border-left: 4px solid var(--accent); }

code {
  padding: .12em .32em;
  color: #8a1420;
  background: #f6e9ea;
  border-radius: 4px;
  font-family: "Cascadia Code", Consolas, monospace;
  font-size: .9em;
}

pre {
  max-width: 100%;
  padding: 18px;
  overflow: auto;
  color: var(--code-ink);
  background: var(--code);
  border-radius: 10px;
  line-height: 1.5;
  tab-size: 4;
}

pre code { padding: 0; color: inherit; background: transparent; border-radius: 0; }

table {
  display: block;
  width: max-content;
  max-width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
}

th, td { padding: 10px 12px; text-align: left; vertical-align: top; border: 1px solid var(--line); }
th { background: var(--soft); }

.document-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  margin-top: 22px;
  padding: 18px 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.site-footer { padding: 25px 0; color: #cbd5e4; background: #151d2c; }
.site-footer a { color: #fff; }

@media (max-width: 850px) {
  .lab-grid { grid-template-columns: 1fr; }
  .lab-card { min-height: 0; }
}

@media (max-width: 560px) {
  body { font-size: 16px; }
  .shell { width: min(100% - 20px, 1080px); }
  .header-label { display: none; }
  .landing, .document-page { padding-block: 32px 48px; }
  .notice, .route, .lab-card, .document { padding: 20px; border-radius: 10px; }
  pre { margin-inline: -8px; padding: 14px; border-radius: 7px; }
}