<Solved>Change color of System message 'OS_EMAIL_CANT BE SEND'

Hello,
I want to change the color of the System message 'OS_EMAIL_CANT BE SEND' from green to red. How can I do this

I inserted html code in the language file but it does not work.
Any ideas?

Thank you
Richard

Edit:
I did a <h6>....</h6>in the language file, made changes in my less file and now it works.

OK, Richard