Lightbox Popup breaking the code on my page.

I use FMG Suites for our website.  I am trying to create a lightbox form that auto pops up when some someone visits the page.  I've created it and it works perfectly.  However it throws off the alignment of the rest of the page.  Is there a simple way to fix this?  

If you could share the webpage where the lightbox is embedded it would be great, so we can be able to check this issue.

We'll wait for your response.

Thank you!