My editor looks strange, what happened?

Clear Cache and refresh the page,

This is likely from the “Hey” theme you’re using.

I installed this theme on a fresh WordPress site, with no plugin at all… and I saw the same small text size and input fields in the editor.

When I revert to the default Twenty Twenty-Four theme, everything gets bigger.

See a side-by-side comparison here: https://s3.amazonaws.com/i.snag.gy/lTa9nh.jpg

Those two screenshots are from the same blank WordPress site with no plugin: the only difference is the theme!

Of course, you can (temporarily) switch themes to confirm this.

Thanks! I changed the font of these titles but this is not reflected in the editor.

See for example https://marcoraaphorst.nl/68301/de-terugkeer-van-de-startpagina/

Is there a way to tweak this so both frontend and backend look the same?