AdminLte/scss/dark/bootstrap/_card.scss

// Base styles

.card {
  background-color: $card-bg-alt;
  border: $card-border-width solid $card-border-color-alt;
}

.card-body {
  color: $card-color-alt;
}

// Optional textual caps

.card-header {
  color: $card-cap-color-alt;
  background-color: $card-cap-bg-alt;
  border-bottom: $card-border-width solid $card-border-color-alt;
}

.card-footer {
  color: $card-cap-color-alt;
  background-color: $card-cap-bg-alt;
  border-top: $card-border-width solid $card-border-color-alt;
}

// Header navs

.card-header-tabs {
  @if $nav-tabs-link-active-bg != $card-bg {
    .nav-link.active {
      background-color: $card-bg-alt;
      border-bottom-color: $card-bg-alt;
    }
  }
}