version 1.3.3

When using a class name that has a character that has to be escaped, for example class="some@class" the required css would look like this: .some\@class but if i feed that into purifycss it gets un-escaped.

so

.class\@name {width: 2vw}

becomes

.class@name {
  width: 2vw;
}

and does not work anymore

here is a example: https://runkit.com/jsnanigans/5a062d8012da6d0012bde28c