CSS Multi-column Layout is a module of CSS that adds support for multi-column layouts. Support is included for establishing the number of columns in a layout, as well as how content should flow from column to column, gap sizes between columns, and column dividing lines (known as column rules) along with their appearance.
.container {
column-count: 3;
}
Source: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Columns