I followed the document supplied by Sencha and created an extension of my own. Now I want to use css to make my extension beautiful.

I read the instruction supplied by Sencha. I define my extension in the package.json file like this:

Code:
    "architect": {
        "compatFrameworks": [
            "touch23"
        ],
        "classes": [
            {
                "className": "sencha.login.LoginPanel",
                "definition": "LoginPanel.js",
                "js": [
                    "loginpanel.js"
                ]
            }
        ]
    },
    "css": [
        {
            "path": "resources/css/loginpanel.css"
        }
    ]
I predefined some styles in the css file.

Then I use my extension to develop my application. The extension is imported successfully, but unfortunately the styles defined in the css file is missing. WHY?
Is there any good example? I searched all the extension in the market of sencha and found nothing useful.

Is this a bug of Sencha Architect? I did follow the instruction about how to create an user extension but failed. Any suggestion?