If you find that your popup is not using your theme styles as it should be, then look to your code to make sure your theme styles are applying globally.

This is usually the case when your theme doesn’t have defaults. For example, let’s say you have a CSS selector that looks like this:

#content ul

This is going to apply the styles to lists that are only inside the content <div>. Which means any <ul> elements that you have in a popup will not inherit these styles.

If that is the case, the most effective solution is to make adjustments to the site theme so that the same styles are applied throughout your site.  Contact your theme author or site admin to the request the change if you do not have direct control over the styles in use on your site.

In this example, all it requires is changing your CSS selector from 

#content ul

to

 ul