Thank you text not showing as expected

Hi there! When I view my Thank You page, it looks like there's a white box behind the text, but when I actually use the page to submit, it looks like the screen shot attached here. I thought that I had already addressed this in a previous help-ticket, and added some CSS to fix it, but now it's doing it again. How can I correct this? 

Thank you for contacting us.

If I understood your question correctly you want that background color of your thank you page is white. 

You can achieve that by Injecting Custom CSS.  Inside of your Form Builder select Setup & Embed tab, then click on Preferences, then select Form Styles tab and inside of Inject Custom CSS field at the bottom of existing code paste this code:

#stage {

background: #FFFFFF!important;

}

When you add this code your Thank You page will look like this. 

Hope this will help. Let us know if you need further assistance.