How can I decrease the font size of the showAlertDialog title?

How can I decrease the font size of the showAlertDialog title?

A (dirty) way is to overwrite the .dialog-title class of the palm css file. But this affects all alert dialogs of your app.

.dialog-title {
font-size:5px !important;

}

A better way is to use your one dialog template with:

this.controller.showDialog({
       template: 'dialogs/sample-dialog',
       assistant: new SampleDialogAssistant(this),
       wisdom: randomLorem(),
       preventCancel:true
 });

See Palm Developer Guide for more information.