Can’t change colour of excerpt text on Blog page

Hello. I don’t seem to be able to get the subtitle or excerpt text to change colour on my Blog page. I also don’t seem to be able to get the header image overlay to appear to make it easier to read my text. Any suggestions on how to rectify? Thanks very much.

Hello there,

I hope you are doing well today.

Could you please provide a link to your website so that I can inspect the page layout that you have and possibly provide some code to help?

Best Regards,
Support