column-span

column-span: none;

column-span: all;

<section id="default-example">
  <div class="multicol-element">
    <p>
      London. Michaelmas term lately over, and the Lord Chancellor sitting in
      Lincoln's Inn Hall.
    </p>
    <div id="example-element">Spanner?</div>
    <p>
      Implacable November weather. As much mud in the streets as if the waters
      had but newly retired from the face of the earth, and it would not be
      wonderful to meet a Megalosaurus, forty feet long or so, waddling like an
      elephantine lizard up Holborn Hill.
    </p>
  </div>
</section>

.multicol-element {
  width: 100%;
  text-align: left;
  column-count: 3;
}

.multicol-element p {
  margin: 0;
}

#example-element {
  background-color: rebeccapurple;
  padding: 10px;
  color: #fff;
}

/* 关键字值 */
column-span: none;
column-span: all;

/* 全局值 */
column-span: inherit;
column-span: initial;
column-span: revert;
column-span: revert-layer;
column-span: unset;

<article>
  <h2>这是一个跨越了所有的列的标题</h2>
  <p>h2 元素应该跨越所有列。文本的其余内容应该分布在各列中。</p>
  <p>这是一些使用 CSS `columns` 属性分成三列的文本。文本在各列中均匀分布。</p>
  <p>这是一些使用 CSS `columns` 属性分成三列的文本。文本在各列中均匀分布。</p>
  <p>这是一些使用 CSS `columns` 属性分成三列的文本。文本在各列中均匀分布。</p>
  <p>这是一些使用 CSS `columns` 属性分成三列的文本。文本在各列中均匀分布。</p>
</article>

article {
  columns: 3;
}

h2 {
  column-span: all;
}