this is an interesting point (I've up-voted you). But my gut feeling is that it doesn't matter. While I don't have any experimental data, I have to imagine th

this is an interesting point (I've up-voted you). But my gut feeling is that it doesn't matter. While I don't have any experimental data, I have to imagine this rendering penalty is in the noise of page/site performance. Asset packaging, gzip, using front end static server, etc are probably orders of magnitude more important for page rending speed than DOM traversal of CSS selectors.