Email is one of the best ways to engage with your users, especially during the holiday season. However, if you want to stand out, no matter how beautiful your emails are, you need to make sure they render correctly in your reader's inbox, regardless of what email client they're using. Creating responsive email is not an easy task, and there are various reasons for that.
First, there is no standard in the way email clients render HTML. This is true for email clients from different companies, such as Outlook and Apple Mail, but not only. Even different versions of Outlook, such as Outlook 2003, Outlook 2013 and Outlook.com, render HTML differently.