Background color in Newdle notifications

A very minor comment about Newdle:
when I receive the below email, I can't help thinking that the listed slots are unavailable because they are on red background, even though it is clearly marked that these are available dates. Each time I (shortly) make the same mistake... Maybe changing the background color would help...

Start by locating the Newdle notification email template and the styles that control the listed dates' background color. Compare the rendered notification with the attached image, then verify that available dates are visually distinguishable from unavailable ones without relying only on the label.

Written by the indexing model from the issue text.