Issue #3316719 by jonathan1055, jaydee1818: Add solid background for non-link...

.scheduler-admin-form > .dropbutton-wrapper {

  width: 30%;

}

/* Add default background to dropbutton items in Claro theme. This should only

   affect the non-link group title items, and avoid them being transparent.

   See https://www.drupal.org/project/scheduler/issues/3316719

   and https://www.drupal.org/project/drupal/issues/3317323 */

.scheduler-admin-form .dropbutton__item:first-of-type ~ .dropbutton__item {

  background-color: #f2f4f5;

}