How does the .jss function work in the Titanium mobile SDK?

I have found https://stackoverflow.com/a/3129609/ and some other blogs and posts. None of them explain how this JSS thing really works ....

I am trying to make a simple JSS implementation only to test how this thing works and implements it for various Android devices.

app.js

var window = Ti.UI.createWindow({
    className : "winodow"
});
user_window.open();

-------------------------

app.android.jss

.window {
    background-color: #fff;
}

This works fine, but changing it to:

-------------------------

app.android.high.jss

.window {
    background-color: #333;
}

app.android.medium.jss

.window {
    background-color: #666;
}

app.android.low.jss

.window {
    background-color: #999;
}

does not affect the appearance of the window.

Even the announcement

which seems like they are not working in the desired way.

I use titanium

<sdk-version>1.7.6.v20120320183239</sdk-version>

and simulator

  Android-2.3.3, API Level 10, HVGA

It is not possible to find clear documentation for implementing JSS in titanium.

Unable to add new tag --- JSS ---