Sometimes you want to style your "Add to cart " button differently than your other main buttons.
You can do this by adding a bit of custom styles. First, open up your theme editor (navigate to /admin/themes, click “Actions” on the copy of our theme, and then click “Edit code”).
You’ll be looking for the theme.scss.liquid file in your assets folder. At the bottom of that file, add this:
Use hex color codes as values above to get exactly the color you're looking for.