/* SRM Nursing Tutor — shared styles.
   No external fonts or CDNs, so the site works on any host and offline. */

:root {
  --primary: #0d9488;
  --primary-dark: #0f766e;
  --ink: #0f172a;
  --body: #334155;
  --muted: #64748b;
  --line: #e2e8f0;
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --warn-bg: #fffbeb;
  --warn-line: #fcd34d;
  --max: 860px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  color: var(--body);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

/* ---- header ---- */
header {
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav {
  max-width: var(--max);
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.brand {
  font-weight: 800;
  font-size: 18px;
  color: var(--ink);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 9px;
  margin-right: auto;
}

.brand .mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 15px;
  font-weight: 800;
}

.nav a.link {
  color: var(--body);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  white-space: nowrap;
}

.nav a.link:hover,
.nav a.link[aria-current="page"] { color: var(--primary); }

/* ---- layout ---- */
main {
  max-width: var(--max);
  margin: 0 auto;
  padding: 40px 20px 72px;
}

h1 {
  font-size: 2rem;
  line-height: 1.25;
  color: var(--ink);
  margin: 0 0 8px;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.3rem;
  color: var(--ink);
  margin: 40px 0 12px;
  letter-spacing: -0.01em;
}

h3 { font-size: 1.05rem; color: var(--ink); margin: 26px 0 8px; }

p { margin: 0 0 16px; }

ul, ol { margin: 0 0 16px; padding-left: 22px; }
li { margin-bottom: 8px; }

a { color: var(--primary-dark); }

.lede { font-size: 1.12rem; color: var(--muted); margin-bottom: 28px; }

.updated {
  font-size: 0.9rem;
  color: var(--muted);
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 8px;
}

/* ---- components ---- */
.hero { padding: 28px 0 8px; }

.badges { display: flex; flex-wrap: wrap; gap: 8px; margin: 20px 0 28px; }

.badge {
  font-size: 0.82rem;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 999px;
  background: rgba(13, 148, 136, 0.1);
  color: var(--primary-dark);
  border: 1px solid rgba(13, 148, 136, 0.25);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.card {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px;
  background: var(--bg-soft);
}

.card h3 { margin: 0 0 6px; font-size: 1rem; }
.card p { margin: 0; font-size: 0.95rem; color: var(--muted); }

.callout {
  border: 1px solid var(--warn-line);
  background: var(--warn-bg);
  border-radius: 12px;
  padding: 16px 18px;
  margin: 24px 0;
}

.callout p:last-child { margin-bottom: 0; }

.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  padding: 12px 22px;
  border-radius: 10px;
  border: 0;
}

.btn:hover { background: var(--primary-dark); }

.btn.secondary {
  background: transparent;
  color: var(--primary-dark);
  border: 1px solid var(--line);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 18px 0 24px;
  font-size: 0.95rem;
}

th, td {
  text-align: left;
  padding: 11px 12px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

th { color: var(--ink); font-weight: 700; background: var(--bg-soft); }

details {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 18px;
  margin-bottom: 10px;
  background: var(--bg-soft);
}

summary { font-weight: 600; color: var(--ink); cursor: pointer; }
details[open] summary { margin-bottom: 10px; }
details p:last-child { margin-bottom: 0; }

/* ---- footer ---- */
footer {
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
}

.foot {
  max-width: var(--max);
  margin: 0 auto;
  padding: 32px 20px;
  font-size: 0.92rem;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  align-items: center;
}

.foot a { color: var(--muted); text-decoration: none; }
.foot a:hover { color: var(--primary-dark); }
.foot .spacer { margin-left: auto; }

@media (max-width: 600px) {
  body { font-size: 16px; }
  h1 { font-size: 1.6rem; }
  main { padding: 28px 18px 56px; }
  .nav { gap: 14px; padding: 12px 18px; }
  .foot .spacer { margin-left: 0; width: 100%; }
}