This actually makes me a little sad. I have a really nice custom css theme in ProtonMail and they don’t support it in the new version
Your CSS appearx to make it look very like Gmail
I dom’t see it myself, I just found their pastel muted purple difficult to read so I made the colours more distinct
Looks very like the folder list on Gmail desktop dark mode to me.
But then I guess it’s difficult to make email look particularly different.
The new version looks even more like Google. I guess that’s on purpose though as it is gmail users they are trying to get signed up
edit… it seems there is a theme in the new one that is similar to what I have currently. Also the blue bar disappears when you turn on notifications of dismiss the banner