HTML mail over plain text

Hello,

I am struggling with this issue for quit a while now ...
I would like to get rid of the boring plain text automated mailing which is included into mybb.

I attended the question on the mybb community forums, but nobody seemed to get an answer to it ... In this stage I can only change the mail templates but not the way how it looks like because CSS and HTML markup is excluded in plain text mail headers.

kind regards

I will share it with you m8 ;)
let's figure out how that PM system works :p

I sent you a PM with my email... thank you very much!

@zyra - do you use html templates for all notification emails (PM, buddy request, etc)?

P.S. thank you for your email!

Until now I am only using it for notifications of new posts in subscribed topics... I could extend it to all kinds of mails and I am also intended to do so ... but need to find the time first.

I applied core changes (thx @Shade) and add my CSS and html into lang file. Unfortunately the css part is missing in sent emails :( Any clue? I use MyBB Patches plugin mentioned above :/

EDIT: Here is my code:
https://jsfiddle.net/Eldenroot/11tuuaq7/37/

Watch out for changes applied by Patches, you need to wrap each line into quotes and add the dot (".") operator to join them.

@Shade - hmm, thank you for your reply. Anyway I tried again without "Patches" - applied changes manually into functions.php file. Same result :( not working css. Can you please check briefly the code provided above if it is fine? I am lost :( Thank you!

Should be fine. However, consider that email providers differ in their CSS syntax support. Check this page and play around with it.

I tried everything, css part is not added into email. I use SMTP over Gmail, maybe is that the issue?

@Shade - please, can you write me how to wrap each line and join them together? Maybe there is an issue (I must doing something wrong). Thank you very much!