simple-dark-mode-for-wp-dashboard/assets/scss/_mixins.scss

/*
 * Button mixin- creates a button effect with correct
 * highlights/shadows, based on a base color.
 */
@mixin button($button-color: var(--color-button), $button-text-color: #fff) {
  background-color: $button-color;
  border-color: $button-color;
  color: $button-text-color;

  &:hover,
  &:focus {
    // background: lighten($button-color, 3%);
    // border-color: darken($button-color, 3%);
    color: $button-text-color;
  }

  &:focus {
    box-shadow: 0 0 0 1px #fff, 0 0 0 3px $button-color;
  }

  &:active {
    // background: darken($button-color, 5%);
    // border-color: darken($button-color, 5%);
    color: $button-text-color;
  }

  &.active,
  &.active:focus,
  &.active:hover {
    background-color: $button-color;
    // border-color: darken($button-color, 15%);
    // box-shadow: inset 0 2px 5px -3px darken($button-color, 50%);
    color: $button-text-color;
  }
}