twitter/css-flip — pull request #3 by mathiasbynens (2014-02-25 07:07:27+00:00)
Title: Avoid crashing on certain unknown CSS properties

CSS like the following:

```css
p {
__proto__: 42;
toString: lolwat;
}
```

…causes css-flip to crash. While these properties are invalid CSS, in general it would be better to just make css-flip preserve any unrecognized properties.

This patch avoids the crash.