src/scss/bootstrap-4.0.0-alpha.6/scss/mixins/_alert.scss

   1 // Alerts
   2
   3 @mixin alert-variant($background, $border, $body-color) {
   4   background-color: $background;
   5   border-color: $border;
   6   color: $body-color;
   7
   8   hr {
   9     border-top-color: darken($border, 5%);
  10   }
  11   .alert-link {
  12     color: darken($body-color, 10%);
  13   }
  14 }