Now it’s fine. It was definitely the caching before and not my browser problem 🙂
First I would recommend building that section with our page header add-on as it’s built for that:
https://docs.generatepress.com/article/page-header-overview/
Background images aren’t responsive by nature unfortunately.
In your case it’s probably best to switch out the image specifically for mobile. If you decide to stick with Sections, then this is the CSS:
@media (max-width: 768px) {
.home #generate-section-1.generate-sections-container {
background-image: url(https://MOBILE-IMAGE-URL-HERE);
}
}
Let me know if you decide to use page header add-on as it will be different code.
As for the font, you can adjust in Customizer > Typography > Headings > H1 with mobile toggle on.