remove trailing { } ;

Hi Ryan,

This PR allow to prevent error when regular CSS already exists in the page

example:
```css
img
  vertical-align: middle

:focus {
  outline-color: transparent;
  outline-style: none;
}

body
  background: #eee
  color: white
```

without the fix will be generated:
```css
img {
  vertical-align: middle;
}

:focus { {
  outline-color: transparent;;
  outline-style: none;;
}

};

body {
  background: #eee;
  color: white;
}
```

With the fix:
```css
img {
  vertical-align: middle;
}

:focus {
  outline-color: transparent;
  outline-style: none;
}

body {
  background: #eee;
  color: white;
}
```

Hope you will like it,
J.