I want to value spacing at csstree 2.0.0

version: csstree 2.0.0

expected
```
border-bottom: 2px #f0f0f0 solid;
box-shadow: 0 -5px 5px 0 rgba(0, 0, 0, 0.05);
```

result
```
border-bottom: 2px#f0f0f0 solid;
box-shadow: 0-5px 5px 0 rgba(0, 0, 0, 0.05);
```

result works to modern browser.
But I unfortunately apply to IE11.
So I want to spacing to values.

How can I do this??

Help me please.

Thanks :)