Automattic/_s — pull request #441 by rizqyhi (2014-03-20 13:05:17+00:00)
Title: Fix overlapping custom header preview

When we need to setup a different background for the preview, we better give it a padding. But it breaks and overlapping the container. Adding 'box-sizing' fixed it.
screenshot: http://cl.ly/image/0U2K1J1H3l2J