:root {
  --bg: #0d0f13;
  --panel: #14171d;
  --text: #d8dade;
  --muted: #96989e;
  --line: #23262d;
  --verbal: #6094d2;
  --analytical: #6cbeaa;
  --downshift: #c4966e;
  --sleep: #6e69a5;
  --rampup: #deba64;
  --accent: #6094d2;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

main { max-width: 720px; margin: 0 auto; padding: 2.5rem 1.25rem 5rem; }

/* nav: sticky, one line, scrolls horizontally on narrow screens instead of wrapping */
nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(13, 15, 19, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  display: flex;
  gap: 1.4rem;
  padding: 0.85rem 1.25rem;
  overflow-x: auto;
  white-space: nowrap;
  justify-content: center;
}
nav a { color: var(--muted); text-decoration: none; font-size: 0.95rem; }
nav a:hover { color: var(--text); }
nav a.active { color: var(--text); border-bottom: 2px solid var(--accent); padding-bottom: 2px; }
nav a.brand { color: var(--text); font-weight: 650; }

h1 { font-size: clamp(1.6rem, 4.5vw, 2.1rem); line-height: 1.25; margin: 0 0 1rem; }
h2 { font-size: 1.35rem; margin-top: 2.4rem; border-bottom: 1px solid var(--line); padding-bottom: 0.4rem; }
h3 { font-size: 1.1rem; margin-top: 1.8rem; }

a { color: var(--accent); }
a:hover { text-decoration: underline; }

p.lead { font-size: 1.15rem; color: var(--muted); }

/* primary and secondary actions */
p.cta { display: flex; gap: 0.8rem; flex-wrap: wrap; margin: 1.6rem 0; }
.btn {
  display: inline-block;
  background: var(--accent);
  color: #0b0d11;
  font-weight: 600;
  text-decoration: none;
  padding: 0.6rem 1.2rem;
  border-radius: 7px;
}
.btn:hover { text-decoration: none; filter: brightness(1.1); }
.btn.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--line);
}

/* tables scroll sideways on small screens instead of breaking the layout */
table { border-collapse: collapse; width: 100%; margin: 1.2rem 0; font-size: 0.92rem; display: block; overflow-x: auto; }
th, td { border: 1px solid var(--line); padding: 0.5rem 0.7rem; text-align: left; vertical-align: top; }
th { background: var(--panel); }

code, pre { background: var(--panel); border-radius: 5px; font-size: 0.88em; }
code { padding: 0.12em 0.4em; }
pre { padding: 1rem; overflow-x: auto; }
pre code { padding: 0; background: none; }

blockquote { border-left: 3px solid var(--line); margin-left: 0; padding-left: 1rem; color: var(--muted); }

/* generated table of contents on document pages */
.toc {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.9rem 1.2rem;
  margin: 1.4rem 0 2rem;
  font-size: 0.92rem;
}
.toc .toctitle { display: block; font-weight: 650; margin-bottom: 0.4rem; color: var(--muted); }
.toc ul { margin: 0; padding-left: 1.1rem; }
.toc li { margin: 0.18rem 0; }
.toc a { color: var(--text); text-decoration: none; }
.toc a:hover { color: var(--accent); }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 0.9rem; margin: 1.6rem 0; }
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  border-radius: 8px;
  padding: 1rem 1.1rem;
}
.card h3 { margin: 0 0 0.4rem; font-size: 1.02rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.9rem; }

.notice {
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  padding: 0.9rem 1.1rem;
  color: var(--muted);
  font-size: 0.95rem;
  margin: 1.6rem 0;
}

ul.sources { padding-left: 1.2rem; }
ul.sources li { margin: 0.5rem 0; }

footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
}

@media (max-width: 480px) {
  nav { justify-content: flex-start; gap: 1rem; }
  main { padding-top: 1.8rem; }
}