column-count

/* キーワード値 */
column-count: auto;

/* <integer> 値 */
column-count: 3;

/* グローバル値 */
column-count: inherit;
column-count: initial;
column-count: unset;

<p class="content-box">
  This is a bunch of text split into three columns
  using the CSS `column-count` property. The text
  is equally distributed over the columns.
</p>

.content-box {
  column-count: 3;
}