Help me ! abput text size

How can we change the software in text font and size? Because I am Chinese users, he will be translated into Chinese and English, but the words above show that the software is relatively small, not very beautiful, hope to have a friend to help me. In which specific file amended. Thank you

In org.jivesoftware.spark

// change this line.

SyntheticaLookAndFeel.setFont(“Dialog”, 12);

In Spark 2.5.3 you can change font size now (Preferences > Appearance)