Custom CSS not working in any questions, except the first one.

@kg96 

Can you provide what code you’re using? and how you have included it.

@Deepak 

The code is very basic, just along the lines of

h1 {
    color: rgb(100,50,20);
}

and it is going in the Custom CSS section under Look and Feel. 

It works fine in a test environment and displays across all questions perfectly there, and it also works perfectly for the first/authentication question of the survey. So I don’t think the code is the problem, but rather something else interfering with it. Any ideas?

Check if you have published the survey as your steps seem correct

@Deepak it is not published, would that make a difference? 

Yes you need to publish the survey to see changes in live link 

@Deepak thanks for the suggestion, but publishing made no difference. I was also just viewing changes in the preview anyway, not the live link.