/* --- Base theme --- */
:root{
  --bg: #ffffff;
  --text: #1f2937;        /* slate-800 */
  --muted: #4b5563;       /* gray-600 */
  --brand: #2563eb;       /* blue-600 */
  --brand-hover: #1d4ed8; /* blue-700 */
  --border: #e5e7eb;      /* gray-200 */
  --card: #f9fafb;        /* gray-50 */
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

/* Layout */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 1.25rem;
}

header {
  border-bottom: 1px solid var(--border);
  background: #fff;
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: .5rem;
}

.brand a {
  font-weight: 700;
  text-decoration: none;
  color: var(--text);
  font-size: 1.125rem;
}

nav {
  margin-top: .5rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  padding: .375rem .5rem;
  border-radius: .375rem;
}

nav a.active,
nav a:hover {
  color: #fff;
  background: var(--brand);
}

main {
  padding: 1.5rem 0 2.5rem;
}

h1, h2, h3 {
  line-height: 1.25;
  margin: 0 0 .6rem;
}

h1 { font-size: clamp(1.6rem, 2vw + 1rem, 2.25rem); }
h2 { font-size: clamp(1.25rem, 1.3vw + .9rem, 1.5rem); }

.lead { color: var(--muted); max-width: 65ch; }

/* Cards / lists */
.grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  margin-top: 1rem;
}

.card {
  border: 1px solid var(--border);
  border-radius: .5rem;
  padding: 1rem;
  background: var(--card);
}

.card h3 { margin: 0 0 .25rem; font-size: 1.05rem; }
.card p { margin: 0; color: var(--muted); }

a.button {
  display: inline-block;
  background: var(--brand);
  color: #fff;
  padding: .5rem .75rem;
  border-radius: .375rem;
  text-decoration: none;
  margin-top: .75rem;
}
a.button:hover { background: var(--brand-hover); }

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 1rem 0;
  color: var(--muted);
  font-size: .95rem;
}

/* Accessibility */
.skip-link {
  position: absolute; left: -9999px; top: auto; width: 1px; height: 1px; overflow: hidden;
}
.skip-link:focus {
  position: static; width: auto; height: auto; padding: .5rem;
  background: var(--brand); color: #fff; border-radius: .375rem;
}