Hello,
I visited your site, as you are using Wp-Bakery code inside that product short description area to display the popup button. And Wp-bakery is not accessible in short description area. So we first have to copy that code to some other dummy page and edit it with Wp-Bakery editor and then define a custom CSS class in column and then put back to short description area.
Then I add custom CSS code according to that class in global custom CSS area under theme settings >> Custom CSS, to get the result in that product page:
.bColor .woodmart-button-wrapper .btn{
background: red;
color: blue;
}
I used the red background and blue text color just to set an example for you you can edit this code and change the colors.
Result: https://jmp.sh/4Yg9x0g
Best Regards.
.
