Don't inject stylesheets with JavaScript

This reverts 4d619d71b1ba7f96011d43c2f45edc441dd26f92 (see #1527), going back to what we had after e13075f6ff2a6a2d1719fe4af27d8099d28a604b (see #881).

To avoid the 404 in the hosted examples, the css is copied to the same relative path when hosted as during development.