Help - Different Width Fields



I have a form with 10 fields. I want the first 6 to be in a two-column format (all input fields, except for one multiple choice for Country). I would like the last four to be one column, 100% width.
I have tried to adjust with #container_ID in the stylesheet with no avail, they still overlap one another.

Has anyone had any success with this and wouldn’t mind sharing?
We have this set up as two step form right now and that seems to work, but after looking at Hotjar forms we are seeing a large drop off after the first step is completed.

Here is a screen shot of my site’s form:

Thank you!