link style buttons shouldn't have padding or border
clean up toc styles
clean up pod css rules

Instead of mixing margins and padding, just use margins everywhere.
Margin collapsing makes it look the same, but it reduces the complexity
of the rules significantly.  Just leave non-syntax highlighted pre sections
using the default styles.  They don't need to match exactly, and the
syntax highlighter will fixed to use those styles eventually.
Merge branch 'pod-style-cleanup'