Ever wondered what's *really* happening under the hood when you apply translateZ(0)? Feeling shaky about how/when pesky CSS style recalcs are slowing things down? Do intermittent page flashes, having to use setTimeout(0) to trigger CSS transitions/animations, or unreliable DOM timers ever get you down? If so, we'll explain how all this black magic works and more through the lens of WebKit's rendering engine. Warning: there might be a lot of blood, guts, and C++ code. For reuse of this video under a more permissive license please get in touch with us. The speakers retain the copyright for their performances.