[LeonM]

CSS in email clients is a mess. Like IE6 on steroids.

I switched to a Windows on my work laptop about 6 months ago, and the native Win 10 email client is probably the worst offender out there. Even the popular mailing lists (like IH, PH, etc) are completely broken to the point of unreadable in Windows 10 Mail.

Mailchimp has a pretty good guides on how to create cross-compatible layouts:

https://templates.mailchimp.com

[canofbars]

From what I remember outlook uses the word rendering engine. Writing any kind of layout that works on all email clients is absolute hell. For most complex layouts it seems most companies just send it as an image with the text being the only other element

[ameen]

As someone who builds email regularly for Outlook - table based layouts work best, if you want to be fancy one could do some fancy VML stuff.

[dehrmann]

Looks like they at least followed the IE pattern of having conditional comments. Embedding IE CSS hacks in one place (and possibly degrading the site) made working with IE almost tolerable.