Change Post Colour Depending On Popularity

I’m wondering if there’s a way to change the background colour of upvoted posts, so when you scroll through, you can see popular ones at a glance. I’ve seen it on the standard WP box, but don’t know the code. I’d quite like to set a rule where the box chnages colour depending on the number of upvotes, so white as standard, then a different colour for 20 upvotes, another for 40, etc.

Thanks for any thoughts you may have. 🙂