bigbluebutton-Github/bigbluebutton-html5/imports/ui/components/chat/chat-dropdown/styles.scss

@import "/imports/ui/stylesheets/variables/_all";

$icon-top-offset: -.4em;
$icon-left-offset: -.1em;
$square-side-length: 1.56rem;

.btn {
  flex: 0 0;
  margin-top: auto;

  span {
    width: $square-side-length;
    height: $square-side-length;
  }

  i {
    color: $color-gray-dark !important;
    top: $icon-top-offset;
    left: $icon-left-offset;
  }   

  &:hover,
  &:focus {
    span {
      background-color: transparent !important;
    }
  }
}