:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --bg: #f8fafc;
  --text: #0f172a;
  --text-muted: #475569;
  --card-bg: #ffffff;
  --border: #e2e8f0;
  --accent: #eff6ff;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #020617;
    --text: #f8fafc;
    --text-muted: #94a3b8;
    --card-bg: #0f172a;
    --border: #1e293b;
    --accent: #1e293b;
  }
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  scroll-behavior: smooth;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

header {
  text-align: center;
  padding: 4rem 0 3rem;
  background: linear-gradient(135deg, var(--primary) 0%, #4f46e5 100%);
  color: white;
  border-radius: 24px;
  margin-bottom: 3rem;
  box-shadow: var(--shadow-lg);
}

header h1 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 1rem;
  letter-spacing: -0.025em;
}

header p {
  opacity: 0.9;
  font-size: 1.1rem;
}

.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 3rem;
  box-shadow: var(--shadow);
}

nav {
  margin-bottom: 3rem;
  padding: 1.5rem;
  background-color: var(--accent);
  border-radius: 16px;
  border: 1px solid var(--border);
}

nav h2 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
  color: var(--text-muted);
}

nav ul {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.5rem;
}

nav a {
  text-decoration: none;
  color: var(--primary);
  font-weight: 500;
  transition: all 0.2s;
  display: block;
  padding: 0.25rem 0;
}

nav a:hover {
  text-decoration: underline;
  transform: translateX(4px);
}

section {
  margin-bottom: 2.5rem;
}

h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

h2::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 24px;
  background-color: var(--primary);
  border-radius: 2px;
}

p {
  margin-bottom: 1.25rem;
  color: var(--text-muted);
  font-size: 1.05rem;
}

ul {
  margin-bottom: 1.25rem;
  margin-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
  color: var(--text-muted);
}

strong {
  color: var(--text);
}

footer {
  text-align: center;
  padding: 4rem 0;
  margin-top: 2rem;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
}

.last-updated {
  font-style: italic;
  margin-top: 1rem;
}

@media (max-width: 640px) {
  header {
    padding: 3rem 1rem;
    border-radius: 0 0 24px 24px;
    margin: -2rem -1rem 2rem;
  }
  
  header h1 {
    font-size: 1.8rem;
  }
  
  .card {
    padding: 1.5rem;
    border-radius: 16px;
  }
  
  nav ul {
    grid-template-columns: 1fr;
  }
}