.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.md-sidebar {
  margin-right: 0.6rem;
}

.md-content {
  max-width: 52rem;
}

.hero {
  padding: 1.2rem 1.4rem;
  margin: 0.7rem 0 1.4rem;
  border: 1px solid var(--md-default-fg-color--lightest);
  border-radius: 0.6rem;
  background: linear-gradient(135deg, var(--md-code-bg-color), transparent);
}

.hero h2 {
  margin-top: 0;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0.8rem;
  margin: 1rem 0;
}

.course-card {
  padding: 1rem;
  border: 1px solid var(--md-default-fg-color--lightest);
  border-radius: 0.5rem;
}

.course-card > :first-child { margin-top: 0; }
.course-card > :last-child { margin-bottom: 0; }

.small-muted {
  color: var(--md-default-fg-color--light);
  font-size: 0.9em;
}

@media (prefers-reduced-motion: no-preference) {
  @keyframes sidebar-enter {
    0% { transform: translateX(-16px); opacity: 0; }
    100% { transform: translateX(0); opacity: 1; }
  }

  .md-sidebar {
    animation: sidebar-enter 0.35s cubic-bezier(.33,1,.68,1) both;
  }

  .md-nav__link {
    transition: color .2s ease, transform .15s ease-out;
  }

  .md-nav__link:hover {
    transform: translateY(-1px);
    color: var(--md-primary-fg-color);
  }
}