full width slider caption doesn’t fit on mobile

Hello Support,
I have created a layer slider with one image and caption on the frontpage of my website. It looks just right on desktop but is totally cut off on mobile portrait view and covers the person in portrait orientation. How can I edit the size and position of the caption for mobile? It should look the same as on desktop.

2nd question: how can I change the styling of headings for posts?

Thank you!