The global secondary theme colors (buttons, borders, price, accents, etc…) can be changed in Real Estate 7 Options > Create a Skin > Secondary Colors (screenshot).
Any page created with Elementor you’ll edit those items directly with Elementor itself, the global color change will not affect them.
If you want to change specific elements or get more specialized we recommend checking out “Find any CSS property, Quickly & Easily“, by using some quick CSS via Real Estate 7 Options > Custom CSS or via your child theme you can easily tweak and customize however you see fit.