Only html attributes that are supported by all major email clients are listed here.
If you need something not that's included (and potentially not universally supported) use attribute or style.
These sources were used to determine what should be included: https://www.campaignmonitor.com/css/color-background/background/ https://www.pinpointe.com/blog/email-campaign-html-and-css-support https://www.caniemail.com/
Open an issue on github if something is missing or incorrectly included.
Use this if there's a attribute you want to add that isn't present in this module. Note that there's a risk that it isn't supported by some email clients.
Use this if there's a style you want to add that isn't present in this module. Note that there's a risk that it isn't supported by some email clients.