/* Smooth light ↔ dark transition */
body {
  transition: background-color 0.3s ease, color 0.25s ease;
}

.navbar {
  transition: background 0.3s ease, box-shadow 0.3s ease;
}

.card {
  transition: background-color 0.3s ease, border-color 0.3s ease,
              box-shadow 0.2s ease, transform 0.2s ease;
}