userstyles/source/tildes-baukula/_buttons.scss

.btn {
  @include color-hover($cyan, $background);

  &:hover,
  &.btn-primary:hover {
    border-color: $pink;
    background-color: $pink;
  }

  &.btn-link {
    border: 1px solid $cyan;
    @include color-hover($cyan, $background);

    &:hover {
      border-color: $pink;
      background-color: $pink;
    }
  }

  &.btn-used {
    color: $background;
    border-color: $pink;
    background-color: $pink;
  }

  &-post button {
    @include color-hover($cyan, $pink);

    &.btn-post-action-used {
      color: $pink;
    }
  }
}