:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --bg-page: #f8fafc;
  --bg-card: #ffffff;
  --text-main: #0f172a;
  --text-muted: #475569;
  --border: #e2e8f0;
  --accent: #eff6ff;
  --badge-bg: #dbeafe;
  --badge-text: #1e40af;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.65;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Header & Navigation */
header {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 50;
}

.nav-container {
  max-width: 960px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.brand {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-main);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.brand span {
  color: var(--primary);
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

nav a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 6px;
  transition: all 0.15s ease;
}

nav a:hover,
nav a.active {
  color: var(--primary);
  background-color: var(--accent);
}

/* Main Container */
main {
  flex: 1;
  padding: 40px 16px;
}

.container {
  max-width: 860px;
  margin: 0 auto;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 36px 32px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.04);
}

/* Typography */
h1 {
  font-size: 1.85rem;
  font-weight: 800;
  margin-bottom: 8px;
  color: var(--text-main);
}

.effective-date {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  display: block;
}

h2 {
  font-size: 1.25rem;
  margin-top: 28px;
  margin-bottom: 10px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border);
  color: var(--text-main);
}

h3 {
  font-size: 1.05rem;
  margin-top: 18px;
  margin-bottom: 8px;
}

p {
  color: var(--text-muted);
  margin-bottom: 14px;
  font-size: 0.96rem;
}

ul {
  padding-left: 24px;
  margin-bottom: 16px;
  color: var(--text-muted);
}

li {
  margin-bottom: 6px;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Callout & Highlight Boxes */
.highlight-box {
  background: var(--accent);
  border-left: 4px solid var(--primary);
  padding: 16px;
  border-radius: 0 8px 8px 0;
  margin: 20px 0;
}

.highlight-box p {
  margin-bottom: 0;
}

.repo-card {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--bg-page);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px;
  margin: 16px 0;
  flex-wrap: wrap;
  gap: 12px;
}

.badge {
  background: var(--badge-bg);
  color: var(--badge-text);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 9999px;
  text-transform: uppercase;
}

/* Footer */
footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 24px 16px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-top: auto;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--text-muted);
}

.footer-links a:hover {
  color: var(--primary);
}

@media (max-width: 640px) {
  .card { padding: 24px 18px; }
  h1 { font-size: 1.5rem; }
}