audio-vis/raw/scss/_controls.scss

.controls {
  right: 0;
  display: flex;
}

.controls button, .menu-icon {
  background-color: rgba(33, 33, 33, .6);
  border: none;
  font-size: 1.4em;
  border-top: 4px solid $primary;
  padding: 1.5rem;
  cursor: pointer;
  color: #fff;
  transition: .5s;

  &.active {
    border-color: $second;
  }

  &:hover {
    background-color: rgba(21, 21, 21, .7);
    border-color: $active;
  }
}