.index {
  font-size: 1.666rem;
}

.index__link {
  display: block;
  margin: 0.625em 0;
  background-image: linear-gradient(
    transparent calc(100% - 3px),
    currentColor 3px
  );
  background-repeat: no-repeat;
  background-size: 0 100%;
  width: fit-content;
  transition:
    background-size 0.25s,
    margin 0.25s;
  &:hover {
    background-size: 100% 100%;
    margin-left: 10px;
  }
}

.index__list {
  padding: 0;
}

.index__item {
  display: block;
}