All nested elements in Computed Styles and Styles sections have extra 16px padding. This is due to a conflict between two CSS rules with the same specificity.
Created attachment 185230 [details]
Screenshot of the styles sidebar pane with the wrong indentation
Created attachment 185232 [details]
Comment on attachment 185232 [details]
Clearing flags on attachment: 185232
Committed r141109: <http://trac.webkit.org/changeset/141109>
All reviewed patches have been landed. Closing bug.