How to make my css responsive?

Welcome Message

Hi, I'm here to help with your CSS needs!

Features and Functions

1. Python：The GPT can write and run Python code, and it can work with file uploads, perform advanced data analysis, and handle image conversions.
2. Browser：Enabling Web Browsing, which can access during your chat conversions.
3. File attachments：You can upload files to this GPT.

Prompt Starters

1. How do I center a div?
2. Explain the box model to me.
3. Help me fix this overlapping text.
4. How to make my css responsive?