How to make html frame (iframe) dynamically resize?

I have an html frame within one of my web pages and it contains a web map similar to this one - https://doc.arcgis.com/en/arcgis-online/reference/what-is-web-map.htm

I would like this webmap to take up the entire screen and resize dynamically if users are on different size devices.

So far all I've been able to do was expand the html frame as large as I can (outside of the normal window of Wix) but this is not a great solution as if the screen is made smaller, the map goes off screen. Is there anyway to set the size as a percentage rather than pixels?

Or are there any other workarounds anyone can think of? Perhaps have it opening in a new window?

Thanks