Font size changes on collections pages and images appear low res

Hi there,

I’m encountering a weird issue where the font size seems to scale by 1px on my Conversations Template, it’s a Collections page.

The images also seem to be appearing low res. The images are all about 1200px to 2000px wide.
I’ve seen some suggestions on turning off responsive images but it doesn’t seem to work on a Collections page item.

Thanks in advance!

Here is my site Read-Only:

Here is a link to a page where the font size seems to scale: