testframe: Actually set the padding
The CSS was targeting node GtkFrame, which is wrong: it is called frame. This commit also assumes the interesting padding is that between the border and the child widget, not the padding around the entire Frame. Some additional hoops must be jumped through to preserve padding values not being changed in either callback. However, the way this is done means I must set the initial paddings to 0, which simplifies main().
Showing with 10 additions and 18 deletions