How Flipkart made their different web and mobile web app with single domain name

Anyone who know how Flipkart made their web and mobile app with single domain name

I am not asking about Responsive web design

Beacause Flipkart web app is not responsive they are using different layouts for mobile and web app by same domain name flipkart.com

I knew the old way for example

Web browser

https://flipkart.com

Mobile browser

https://m.flipkart.com

My Question is how they did with single domain.

How they are mainting two diffent apps in single platform

Below is the screenshot of Flipkart web app and mobile web app

Thank you advance!