.VerticalScrollBar {
  // Note: this should be positioned absolutely
  // by the consuming component
  &-thumb {
    border-radius: 4px;
    background-color:rgba(0,0,0,0.5);
    pointer-events: none;
    opacity: 0;
    transition: opacity 350ms cubic-bezier(0.33,0.66,0.66,1);
    width:100%;
    will-change: opacity, transform, height;
  }
}

.VerticalScrollBar {
  // Note: this should be positioned absolutely
  // by the consuming component
  &-thumb {
    border-radius: 4px;
    border: .5px solid rgba(255, 255, 255, 0.4);
    background-color: rgba(0, 0, 0, 0.5);
    pointer-events: none;
    opacity: 0;
    transition: opacity 350ms cubic-bezier(0.33, 0.66, 0.66, 1);
    width: 100%;
    will-change: opacity, transform, height;
  }
}

Add a slight white border to scroll thumb
Add a slight white border to scroll thumb
