message: style: enhance muc member badge
diff: position: relative;
  &::before {
  + background-color: #fff;
  + border-radius: 6px;
  + color: #000;
  content: attr(data-number-of-members);
  font-size: 12px;
  - line-height: 18px;
  + line-height: 1;
  + margin-right: -1.3em;
  + margin-top: -1.6em;
  + padding: 0.1em;
  position: absolute;
  - right: 0;
  - top: 0;
  + right: 50%;
  + top: 50%;
  }
  &:hover {
  