Improve tooltips

Allow tooltips in div element (currently tooltips only allow items in pre element which is tricky to format). Also fix wrapping, remove gradient fill, and introduce a maximum width of 500px by default.
Fine, this change was a learning opportunity for me somewhat, in that I learned that the style could/should be applied via the css.

So, let's remove all the style changes from this update, and override the pre to a div as the only change.