escaped css variables exported with escaping to javascript

[idoros]

When defining a css variable with escaping, the escape is exported to javascript and will not affect when using through style.

playground

js bin

.root {
    --b\.a: red;
}

is exported as:

"vars": {
    "b\\.a": "--index-b\\.a" // should be: "b\\.a": "--index-b.a"
},