CSS is essentially declarative programming for several different black-box systems. How selectors are written has exponential performance implications. Using t

CSS is essentially declarative programming for several different black-box systems. How selectors are written has exponential performance implications. Using the wrong type of transform might make your page forego hardware acceleration, or use more battery on a mobile device. At least typical programming languages are targeting a known set of environments and devices with known characteristics. You definitely need to understand a lot more than the box model and a handful of gotchas.