I believe http://philschatz.com/css-polyfills.js/ makes this element unnecessary. I've mentioned the issues with having this element in the PDFs before (the number of nested elements affects page-breaking logic).

I don't think a single style (grayscale version of physics which is 2 years old) in webview should drive the canonical HTML format and styling for all our books. More discussion may be needed but my goal for this PR is to get Aloha into webview.