Exit the soure code mode button can't see clearly

[Robot-Dog]

Hi，thank you for the beautiful theme. I like this theme very much，it make me confortable to use.

In the process of using notion-dark-enhanced theme, I think exit source coed button is not clear, I hope it can be improved, thank you.

[adrian-fuertes]

Hey @Robot-Dog! Thank you for leaving an issue. I haven't encountered this one before, I'll look into it :)

[adrian-fuertes]

Hi! I have not been able to replicate this issue in Windows 10 and Typora 1.5.5. Could you confirm the problem is still present in the latest release :)