The polyfill’s css parser was built by following the CSS Syntax 3 specification, the polyfill should be able to process any css stylesheet. It can react to dynamic pseudo-classes like ‘:hover’, to media queries changes or window resize events. It also detects changes to the DOM that may affect the layout of your grid.
There are a few quirks though:
Because the layout is done asynchronously, the polyfill may play badly with other libraries that expect layout to be performed synchronously. This is particularly true if you plan to animate your grid.
The whole polyfill is very sensitive to changes to the “box-sizing” property (and many frameworks like Bootstrap do make use of it); again, this will be ironed out soon but you have to be aware.
The polyfill doesn’t like fixed/absolutely positioned grid items. If you want to use them, just put them in a dummy wrapper, it will work fine.