Meeting page UI customization

Hi ,
I am jist reading through some of the questions in the forum, i am looking to customize UI layout of the meeting page for web, android and ios. Theres no detailed information available as ro what page (js or html or css) contains the meeting screen UI rendering. For web if i have to customize what codes need to be changed i wanted to change the look and feel of the meeting screen alone.

There is no pages, there is a single index html that loads the app. The source code you can find at GitHub GitHub - jitsi/jitsi-meet: Jitsi Meet - Secure, Simple and Scalable Video Conferences that you use as a standalone app or embed in your web application.