Lead Developer
Ah, that’s definitely a little more involved than just adding icons – it would involve creating javascript to deal with the toggle function, and changing the CSS/HTML to include the toggle button.
Something like that might be worth hiring a freelancer for a couple hours to complete for you.
Documentation: http://docs.generatepress.com/
Adding CSS: http://docs.generatepress.com/article/adding-css/
Ongoing Development: https://generatepress.com/ongoing-development