Some fields are showing with different CSS across different systems / browsers

Form working like it should on mac but on PC the drop down fields have a black background when they don't have that selected in the form design. Looking for a way to get this consistent across all major browsers O.S.

I have also cleared cache and web data*

Thanks for your time!

Update:

I got it to work with:

select.form-dropdown {
    background-color: white;
    height: 28px;
    width: 240px;
}
select.form-dropdown > option {
    background-color: white;
}

Although the background was already supposed to be white. 

Thank you for updating us, that code is correct.

The issue is that you have embedded your jotform using full source code of your jotform, so the colors were assigned to select (dropdown) element per some of the other CSS rules on your own website.This was possible since the code was not explicitly given on the jotform itself, but as soon as you did, it had more importance over the code on your website and is now working for you.Do let us know if you have any further issues and we would be happy to assist.