/* ===== CSS Reset ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ===== Mobile-First Base Styles (< 768px) ===== */
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  color: #1f2937;
  background-color: #f3f4f6;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

/* Header & Navigation */
.site-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  background-color: #1e3a8a;
  color: #ffffff;
}

.logo {
  font-size: 1.75rem;
  font-weight: 700;
}

.logo span {
  color: #fbbf24;
}

.nav-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.nav-links a {
  display: block;
  padding: 0.25rem 0.75rem;
  border-radius: 4px;
  transition: background-color 0.2s ease;
}

.nav-links a:hover {
  background-color: rgba(255, 255, 255, 0.15);
}

/* Main layout container */
main {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 1.5rem 1rem;
  flex: 1;
}

/* Bio / Hero */
.bio-hero {
  flex-basis: 100%;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 2rem 1.5rem;
  background-color: #ffffff;
  border-radius: 8px;
  text-align: center;
}

.bio-hero h1 {
  font-size: 1.75rem;
  color: #1e3a8a;
}

.btn {
  align-self: center;
  padding: 0.6rem 1.25rem;
  background-color: #1e3a8a;
  color: #ffffff;
  border-radius: 4px;
  font-weight: 600;
  transition: background-color 0.2s ease;
}

.btn:hover {
  background-color: #2563eb;
}

/* Card Grid */
.card-grid {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.card {
  flex-basis: 100%;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1.5rem;
  background-color: #ffffff;
  border: 2px solid transparent;
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.15);
  border-color: #2563eb;
}

.card h2 {
  font-size: 1.25rem;
  color: #1e3a8a;
}

.tag {
  margin-top: auto;
  font-size: 0.85rem;
  font-weight: 600;
  color: #2563eb;
}

/* Footer */
footer {
  padding: 1.5rem 1rem;
  background-color: #111827;
  color: #d1d5db;
  text-align: center;
  font-size: 0.9rem;
}

footer a {
  color: #fbbf24;
}

/* ===== Desktop Breakpoint (>= 768px) ===== */
@media (min-width: 768px) {
  .site-header {
    flex-direction: row;
    justify-content: space-between;
    padding: 1rem 2rem;
  }

  .nav-links {
    flex-direction: row;
    gap: 1rem;
  }

  main {
    padding: 2rem;
  }

  .bio-hero {
    padding: 3rem 2rem;
  }

  .bio-hero h1 {
    font-size: 2.5rem;
  }

  .card-grid {
    flex-direction: row;
    justify-content: space-between;
    gap: 0;
  }

  .card {
    flex-basis: 30%;
  }
}