Customize and Improve Vertical Spacing with the "Spacer" Tool
How to use the Spacer
The spacer is included amongst all the other insert tools. The spacer can be added, dragged into place within content blocks and adjusted for sizing. There are no gadget settings currently for this tool.
Impact of this Google Sites Update
This is a small but helpful update. Previously users were adding empty text boxes, which may behave differently than this spacer for responsive web design purposes. It also seems more flexible and exact. As the Google Sites team states: "This feature provides more flexibility, especially when designing a vertical layout, and generally makes template and webpage design much easier."
This is just another handy aesthetic feature for Google Sites that helps web designers like ourselves design beautiful responsive Google Sites templates. Lately updates have been aesthetic, like the social links bar, general site margins settings and templating options.
Add a spacer between elements
You can use spacers to re-arrange your site layout and add empty spaces between different items.
On a computer, open a site in new Google Sites.
On the right panel, click Insert Spacer.
You can drag and drop to move the spacer, and you can adjust the size of the spacer.
To publish your changes, at the top right, click Publish.
https://support.google.com/sites/answer/90538#zippy=%2Cadd-a-spacer-between-elements