Pages : where are toolbar icons stored?

Hello,

I'm tired of the monochrome design of Pages. So I try to bring a little cheerfulness and above all a little visual ergonomics into this gray world. So I looked for where the toolbar tool logos are stored, via the famous "View Package Contents" command on the application. Then into the depths of the system and the library. Without success (I don't work in the IT field).

Does anyone know where these precious icons are hidden?

Once this path is found, I will look for the same icons in the old Pages to install them in the new Pages. Thank you in advance for your help.