hexo-theme-keep/source/css/layout/_partial/toc.styl

.post-toc-wrap {
  width: 100%;
  font-size: 0.92em;
  box-sizing: border-box;

  .post-toc {

    ol {
      list-style: none;
      margin: 0;
      padding: 0 2px 12px 10px;
      text-align: left;

      &:last-child {
        padding-bottom: 0;
      }

      > ol {
        padding-left: 0;
      }

      a {
        transition-property: all;
        transition();
      }
    }

    .nav-item {
      line-height: 1.8;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .nav {
      .nav-child {
        display: hexo-config('toc.expand_all') ? block : none;
      }

      .active > .nav-child {
        display: block;
      }

      .active-current > .nav-child {
        display: block;

        > .nav-item {
          display: block;
        }
      }

      .active > a {
        color: var(--primary-color);
      }

      .active-current > a {
        color: var(--primary-color);
      }
    }
  }
}