Need help CSS styling form

Hi,

I just started using the forminator plugin and I am still learning css. I have been trying to fix this myself, but I really need your help to style my buttons.

• Fixing buttons size:
  Step 1: The “volgende” button should be full width
  Step 2: The “vorige” and “volgende button should be next to each other (in same row) with a little gap / space between them
  Step 3: Should be the same as step 2.
  
  They should work the same on mobile. And I would also like to remove the shadow on active & hover. Also the buttons should be the same size.
• Border-radius of 10px for each button
• Get the dropdown container also radius of 10px

Thank you in advance.

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