Custom CSS change post catagory

Hello,

My site is : https://www.ibbuk.co.uk

and i was wandering if anyone could tell me how:

if a selected a post to be in a certain catagory (for the purpose of example i’ll choose “Live”) and then if a post is in “Live” then the background for post on the main homepage will change to a different colour (the bits in grey)

Anyone know how to do that?

Cheers

James