I'm surprised this didn't mention stacking contexts, which threw me for a loop a couple times: http://philipwalton.com/articles/what-no-one-told-you-about-z-in

I'm surprised this didn't mention stacking contexts, which threw me for a loop a couple times: http://philipwalton.com/articles/what-no-one-told-you-about-z-index/ http://philipwalton.com/articles/what-no-one-told-you-about-... https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Understanding_z_index/The_stacking_context https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Under...