Guide to CSS support in email. Version history 14 November 2017 Outlook.com and the Outlook iOS app added support for CSS background images and some related properties, as well as certain Flexbox and Grid properties.
Using CSS in HTML Emails: The Real Story. Should you be sending HTML emails at all? This is surely a debated issue, but ultimately I say if you have a message you feel would benefit from a nicely designed email you should go for it. If you just want to do it because everyone else on your block is doing it too, don't. If you decide to do it, these are what I consider to be the five golden rules of HTML emails: Only send email to people that opted to receive them.Make sure to create it so that it looks the best it possibly can in all email clients.Don't overdo it. Weekly is probably too often.Send a plain text alternative.Offer and opt-out link and honor it. Email Marketing Field Guide.