how to change font family of dropdown list

hi i'm looking to change the font for the dropdown list below. how can i do that? i've looked it up online but all i see are html tweaks and using jquery.

thanks

If you are referring this form, you have already been able to figure it out. 

However, you might have thought that the injected css code did not applied properly if you are a Mac user. Since, the Mac does not allow you to display option in different font families.

Here is the view of your form on a Mac device:

Here is the view of your form on a Windows device:

Hope, these help you. If you have more questions, please feel free to contact us.