See the site here
In the sidebar there are widgets: the Ephemera widget followed by my custom Facebook likebox widget below, then another Ephemera widget with different content.
As you can see, the Ephemera widget creates a grey box to the left of the header and places a Genericon in it, one for each type of Ephemera display.
The Genericon set contains icons for Facebook, and I'd like to put a similar grey box next to the Facebook widget title and display the Facebook genericon within.
The problem is it's the sidebar, not the Facebook widget, that generates that header and I don't have control of it. So... how would I go about telling to to make a grey box for all sidebar widget headers, and to put genericons in the ones it recognises?
Twenty Fourteen gurus? Li'l help?