Bug 1069306 - Dark screen while searching for networks

just a little house tidying for better reading, let's improve the order of the css classes.
```css
#loading-overlay {
    background-color: #f4f4f4;
}

#loading-overlay h1, 
#loading-overlay p {
    color: #000000;
}

#loading-overlay menu {
  display: none;
}

#loading-overlay menu.showed {
  display: block;
}

#loading-overlay.hide {
  display: none;
}
```
...and then the rest of css items.