.back-to-top {
  bottom: $b2t-position-bottom;
  box-sizing: border-box;
  color: $b2t-color;
  padding: 0 6px;
  transition: bottom $transition-ease;
  sidebar-toggle();

  if (hexo-config('back2top.scrollpercent')) {
    width: initial;
  } else {
    width: 24px;
  }

  &:hover {
    color: $sidebar-highlight;
  }

  &.back-to-top-on {
    bottom: $b2t-position-bottom-on;
  }
}