Change the size of text in image blocks on mobile

I'm trying to add some custom code to alter the text of my site on mobile as there's no functionality to do this in the style editor, other than dynamic scaling which is unpredictable and inconsistent across blocks.

I added the following to adjust my headings, which was straight forward but I'm struggling to target text within image blocks

@media only screen and (max-width: 640px) { h2 {font-size:2em;} }

Thanks

@olipowell can you share site url to check image block's code?

It's unpublished here @ www.rejectsupply.com Test123

@olipowell

@media screen and (max-width:640px) {
.image-title-wrapper * {
   font-size: 10px !important;
}
}

5 minutes to check & found the code.