How to I enable styling for inner pages

Hey team,

I am using plugin to sign the petition.
I was able to achieve the functionality part, just that I need to beautify it with the bit of CSS.
Was wondering if you could help me.

Here is my page where I have used Petition shortcode and the text.
There is a "PopUp" "Read the petition" My client doesn't want popup.

They are asking something like this.
On left site the content of the petition, on right side they need a signup form for petition
Could you please help me do this?

Or please let me know how can I do this.