nth-child `1 of x` space removal

[ernieayala]

When using a selector such as :nth-child(1 of .item) it is compressed down to :nth-child(1of.item) thus breaking the selector.

[XIYU11864]

@ernieayala You can use -O0. This leval remove most line breaks and spaces but dosen't break something like :nth-child(1 of .item). Or you can use https://github.com/clean-css/clean-css#how-to-keep-a-css-fragment-intact .