Google's new Inbox service is great, but it only works on Android, iOS and Chrome. If none of those are your preferred method for accessing your email, The Zinx shows you how to change your browser's user agent to access Inbox anywhere.
To access Inbox from Safari or Firefox, you just need to change your User Agent over to Chrome when you're on the inbox.google.com page. Once you've done that, Inbox will load up just like it does in Chrome. It's a bit of a pain to do it every time, but better than nothing.