Well, first thing i’d do is find out what’s turning the text black.
Expand your style panel over there on the right, and look for any rule defining the color of the element.
(If there is none, you just define a rule for the specific element; if there is one, change or overwrite it.)
The color of the text on the button will be blue not red. Even though it appears to be over-written by the second rule, it is more specific and holds more weight.
It’s difficult to give you the answer without playing with it hands on, but I would actually try adding that first rule.
If it works with an !important tag then you know you need an even higher specificity. Ideally you should be able to find the exact rule that is setting the text to dark. (It is the text you are talking about?). My first thought is the class ‘btn-light’.
Note Dave is talking about the background-color, so I may have the wrong end of the stick, but I still think the solution is probably to add a more specific rule. That’s if this can’t just be fixed in elementor’s ui.