.app-shell {
  min-height: 100vh;
  padding: 0 0 var(--space-xl);
}

.app-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: color-mix(in srgb, var(--color-surface) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-md);
}

.app-header__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-sm);
  align-items: center;
  padding-top: var(--space-sm);
  padding-bottom: var(--space-sm);
}

.app-header__brand {
  display: flex;
  align-items: center;
}

.app-brand-link {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--color-text);
}

.custom-logo-link {
  display: inline-flex;
  align-items: center;
}

.custom-logo-link .custom-logo,
.app-brand-link .custom-logo {
  width: auto;
  max-height: 54px;
}

.app-brand-text {
  font-size: var(--font-size-h4);
  line-height: var(--line-height-h4);
  font-weight: var(--font-weight-h4);
}

.app-header__nav {
  overflow-x: auto;
}

.app-menu {
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin: 0;
  padding: 0;
}

.app-menu a {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  font-size: var(--font-size-menu);
  line-height: var(--line-height-menu);
  font-weight: var(--font-weight-menu);
}

.app-header__actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-xs);
  flex-wrap: wrap;
}

.app-main {
  width: 100%;
}

.app-container {
  width: min(var(--container-max), calc(100% - (var(--space-md) * 2)));
  margin: 0 auto;
}

.app-container--narrow {
  width: min(920px, calc(100% - (var(--space-md) * 2)));
}

.app-grid {
  display: grid;
  gap: var(--space-md);
}

.app-grid--stack {
  grid-template-columns: 1fr;
}

.app-grid--courses {
  grid-template-columns: 1fr;
}

.section-head {
  margin-bottom: var(--space-md);
}

.hero-banner {
  margin-bottom: var(--space-lg);
}

.hero-kicker {
  display: inline-block;
  margin-bottom: var(--space-sm);
  padding: var(--space-xxs) var(--space-sm);
  border-radius: var(--radius-pill);
  background: var(--color-blue-light);
  font-size: var(--font-size-menu);
  line-height: var(--line-height-menu);
  font-weight: var(--font-weight-menu);
}

.catalog-section {
  margin-top: var(--space-lg);
}

.catalog-home > *:first-child {
  margin-top: 0;
}

@media (min-width: 768px) {
  .app-header__inner {
    grid-template-columns: auto 1fr;
    gap: var(--space-md);
  }

  .app-grid--courses {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  .app-grid--courses {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero-banner {
    padding: var(--space-lg);
  }
}