*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --border: #e5e7eb;
  --text: #111827;
  --muted: #6b7280;
  --accent: #1d4ed8;
  --accent-hover: #1e40af;
  --radius: 8px;
  --max-width: 720px;
}

html { font-size: 16px; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); text-decoration: underline; }

/* ── Layout ── */
header {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  padding: 0 1.5rem;
}
header .inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  height: 56px;
}
header .brand { font-weight: 600; font-size: 0.95rem; color: var(--text); }
header .brand span { color: var(--muted); font-weight: 400; }

main {
  flex: 1;
  padding: 2.5rem 1.5rem;
}
main .inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

footer {
  border-top: 1px solid var(--border);
  background: var(--surface);
  padding: 2rem 1.5rem;
  font-size: 0.85rem;
  color: var(--muted);
}
footer .inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
footer .footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1rem;
  margin-bottom: 0.75rem;
}
footer .footer-links a { color: var(--muted); }
footer .footer-links a:hover { color: var(--accent); }
footer .copyright { margin-top: 0.5rem; }

/* ── Typography ── */
h1 { font-size: 1.75rem; font-weight: 700; line-height: 1.2; margin-bottom: 0.5rem; }
h2 { font-size: 1.2rem; font-weight: 600; margin: 2rem 0 0.5rem; }
p { margin-bottom: 1rem; }
ul, ol { padding-left: 1.5rem; margin-bottom: 1rem; }
li { margin-bottom: 0.25rem; }

.page-intro { color: var(--muted); font-size: 1.05rem; margin-bottom: 2rem; }

/* ── Cards ── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

/* ── App entry on homepage ── */
.app-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.app-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(29,78,216,0.08);
  text-decoration: none;
}
.app-icon {
  width: 56px;
  height: 56px;
  border-radius: 12px;
  background: linear-gradient(135deg, #1d4ed8 0%, #2563eb 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: #fff;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -1px;
}
.app-card-body h2 { margin: 0 0 0.25rem; font-size: 1.05rem; }
.app-card-body p { margin: 0; font-size: 0.9rem; color: var(--muted); }

/* ── Nav links on sub-pages ── */
.sub-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1rem;
  margin-bottom: 2rem;
  font-size: 0.9rem;
}
.sub-nav a { color: var(--muted); }
.sub-nav a:hover { color: var(--accent); }

/* ── Divider ── */
hr { border: none; border-top: 1px solid var(--border); margin: 2rem 0; }

/* ── Callout ── */
.callout {
  background: #eff6ff;
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

@media (max-width: 480px) {
  h1 { font-size: 1.4rem; }
  main { padding: 1.75rem 1rem; }
  header { padding: 0 1rem; }
  footer { padding: 1.5rem 1rem; }
}