How to customize the style of font size selector?

I need to change the font size selector text to “一号, 二号, 三号”. How to customize it?

You can’t, if you’re expecting the numbers to be with Chinese characters and they aren’t, then that is a bug, please report it at the following link: Issues · CollaboraOnline/online · GitHub

While. Thank you! Could I ask which configurations, files, or codes to modify this issue by myself?