Theme style doesn’t work well with my table

Dears.

I have a problem in the form’s table style. I embedded the form (Plumsail form) into a WordPress page, and it seems like the style of the theme affects the form’s style. How I can fix that ?

As you see in the picture below , the header’s width doesn’t fit the rows width. It is because the space of the scrollbar in the header doesn’t shifted to the left as it is in the Dt ( rows below )
screenshoot

I tried this form with another theme and it works well. but I really love WPocean theme and I dont want to change it. So, I hope if you can help me with this small problem.

The page I need help with: [log in to see the link]