How is the web create with just 1html pg, 1css pg, and 1js pg

Question

This website as so many pages like registration page, login page and other page all created with 1html pg, 1css pg, and 1js pg... Please someone explain. How to build something like that
https://code.sololearn.com/Ww14qXlukgUu/?ref=app

Answer 1

OverLord

Html is what you see on browser.
CSS is what you see some attractive things on browsers

JavaScript is what you see some moving things or events are happening on browser.

A website can have many html pages, many CSS files and many JavaScript files for different functionalities.

A website can also contain a single page with registration, login and othe things like contact us, about us

Answer 2

As A͢J - S͟o͟l͟o͟H͟e͟l͟p͟e͟r͟ explained, understanding how to combine html, css and javascript, is a main key to what you want to make OverLord. As you can see that website is made up of those languages.