Low contrast on sended and subject info

I have installed the Latte-blue theme, however I find that there is low contrast in the sender and subject information when a email preview is open. Is that intended to be like this or is it some issue on my side?
See the picture

Reproduce the low-contrast sender and subject information shown in the attached screenshot with the Latte-blue theme and inspect the theme styling responsible for the email preview. Done means confirming whether the contrast is intentional or adjusting it so the sender and subject are clearly readable.

Written by the indexing model from the issue text.