I was typing pretty much the same thing as this feature request from 2019. I too have recently joined the multiple hub club and if the hubs each had a different pale color background it would make it easily obvious which hub you are interacting with. I would suggest a limited palette of pale colors that wouldn't interfere with the usability of the interface but would make it so much easier for us mortals trying to keep everything straight.
Nice light colors like this available as a drop down or color picker on the Settings page would be sweet.
Old request: Setting to change background color
Thanks in advance for your consideration of this request.