How to change the color and font of a GtkLabel

["Norman Black" <stonybrk ix netcom com>]

I want to  change the color and font of a GtkLabel. I assume I do this with
the style.

Questions
Can I modify the style of the label directly, or will this also affect other
labels/widgets.
If I cannot modify directly with side effects then I assume I should copy
the existing style.
Do I need to unref the old style. Or just setting my new style will handle
this.
Do I need to unref my copied style after setting it into the widget so that
it will auto destroy when the widget destroys. Or should I destroy the style
manually when the widget destroys.

Best Regards,
Norman Black
Stony Brook Software