The element I'm referring to is the offset box that is positioned above, to the left and below the main box.
Now creating this with regular HTML and CSS is super easy using absolute positioning and z-index.
However, in email HTML, where you're basically restricted to tables, I can't figure it out. Absolute positioning doesn't appear to be allowed. Most email clients strip it out. I'm not even sure if negative positioning is allowed.
How would you create this? Is it possible/worth even trying?