.thread__collapse {
  height: calc(100% - 50px);
  width: 11px;
  position: absolute;
  top: 50px;
  left: -4px;
  cursor: pointer;

  &::after {
    display: block;
    content: '';
    position: absolute;
    left: 5px;
    top: 0;
    border-left: 1px dotted var(--color35);
    height: 100%;
  }

  &:hover::after {
    transform: translateX(-1px);
    border-left: 3px solid var(--color10);
    z-index: 10;
  }
}

.thread__collapse_collapsed {
  width: 18px;
  height: 18px;
  top: 12px;
  left: 0;
  display: flex;
  text-align: center;
  opacity: 0.8;
  border-radius: 2px;
  border: 1px solid;

  &::after {
    display: none;
  }

  &:hover {
    opacity: 1;
  }

  &:hover::after {
    transform: translateX(0);
  }
}

.thread__collapse_collapsed > div {
  position: relative;
  top: 6px;
  left: 3px;
  width: 12px;
  height: 2px;
  border-bottom: 2px solid;

  &::before,
  &::after {
    content: '';
    width: 100%;
    height: 2px;
    border-bottom: 2px solid;
    position: absolute;
    top: -4px;
    left: 0;
  }

  &::after {
    top: 4px !important;
  }
}