Keep in mind that applications (particularly older versions) may use a completely different rendering engine from your day-to-day browser, and the results of various styles can be anywhere from non-existent to buggy.
Given that, you may see differences in the rendered output in Outlook, compared to what you'd see in the browser. This is true of other email clients as well. You may want to have a look at the following site to see what is and isn't possible with Outlook, etc.:
https://www.campaignmonitor.com/css/email-client/outlook-2007-16/