:root {
  --bg: #ffffff;
  --text: #1f2937;
  --muted: #4b5563;
  --line: #e5e7eb;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --card: #f9fafb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

.container {
  max-width: 940px;
  margin: 0 auto;
  padding: 1rem;
}

header {
  border-bottom: 1px solid var(--line);
}

.site-title {
  margin: 0;
  font-size: 1.2rem;
}

nav {
  margin-top: 0.6rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 0.8rem;
}

nav a {
  display: inline-block;
  text-decoration: none;
  color: var(--accent);
  font-weight: 600;
  border-bottom: 2px solid transparent;
  padding-bottom: 0.1rem;
}

nav a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

nav a.active,
nav a[aria-current="page"] {
  color: var(--text);
  border-bottom-color: var(--accent);
  text-decoration: none;
}

main {
  padding-top: 1.2rem;
  padding-bottom: 2rem;
}

.hero {
  padding-top: 1.3rem;
  padding-bottom: 0.6rem;
}

h1, h2 {
  line-height: 1.25;
}

.lead {
  color: var(--muted);
  font-size: 1.05rem;
}

.grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin-top: 1rem;
}

.card {
  border: 1px solid var(--line);
  background: var(--card);
  border-radius: 10px;
  padding: 1rem;
}

footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.95rem;
}

@media (max-width: 640px) {
  .container {
    padding: 0.9rem;
  }

  nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.3rem;
  }

  nav a {
    padding: 0.2rem 0;
  }

  .hero {
    padding-top: 1.6rem;
  }
}