Help CSS Editor in Widgets

Hi

Is there any example I can use to undertand how to use de CSS editor to give style to the labels text in Widgets? For example, I’m using a Integer Widget, and I want to change the font-size and the font-family. I’ve used .knime-label, .knime-text and so on, but I haven’t seen any change in the label text when I execute the widget. Heeeeeeeelp Please!!!