CSS: What are viewport units vw

An example:

#grid {

display: grid;

grid-template-columns: 1fr 1fr 1fr;

grid-auto-rows: 33vw;

}

Reference:

Viewport Width (vw) – A percentage of the full viewport width. 10vw will resolve to 10% of the current viewport width, or 48px on a phone that is 480px wide. The difference between % and vw is most similar to the difference between em and rem. A % length is relative to local context (containing element) width, while a vw length is relative to the full width of the browser window.

https://css-tricks.com/fun-viewport-units/