Conifgurable list: Change color of header texts

I really like the vertical format provided by this code instead of horizontal cause it allows more fields to be used. However, I now can't seem to control the text color of my headings using the suggested code...

"th {color: #fff;}"

Does this code need to be injected in a certain place? Do I need to use different code to accomplish this now that I've injected the code above?

To which form is your issue related? Please provide us a form URL and tell us to which color do you want to change the headings.

Where to Find My Form URL? 

https://form.jotform.com/201366891142151

I have removed the title headings to get around this, as they were displaying in black and they couldn't be seen well against the background, but I would rather they be there in white as I was able to accomplish before using the code to make the widget responsive.

Thank you for your help.

This should be the correct code to use:

.mobileColumnName {

    color: #ffff!important;

}

Add it to the custom CSS tab of the widget:

Works perfect. Thank you.