Font keeps changing in emails

Font keeps changing in emails

Is there a way to set a permanent default font in emails (specifically email signatures)?
 
We spent hours setting them all up (templates, email sigs etc) and they seem to randomly send in different fonts. Usually Times New Roman, we set everything up in Arial.
 
Sometimes the body of the email stays as Arial, but the signature text sets itself to Times New Roman. Looks very bizarre to recepients :)
 
Kenneth


Moderation Update:

Given that the original post was made before multiple enhancements to the email template editor and preferences, we are closing the post. Feel free to contact support or initiate a new discussion if needed.