My website elements are shifting their positions on different mobile or pc

Question

https://code.sololearn.com/WCHRPSqT12FN/?ref=app

Idk how to put in words but I'll try my best

If you view this on a mobile of different screen size, website is different like elements are on top of each other or occupying other element position and invading their space. But on viewing on pc is also different.
I don't have pc. So I'm coding in mobile

I have noticed that when I opened this link on another mobile the website elements are not in their position, where I've assigned them to be. They're completely in different position

How can I make my website responsive to all devices?

Answer 1

Change width: 100%;

https://code.sololearn.com/W2wb78CownXI/?ref=app