So how can i make it responsive ?

[snoovocz]

Like i mean how can i make the website responsive across all platforms, do i need to use external css or is there any ways ?

[larsblumberg]

Reflex has built-in break points for different screen sizes. Here's a good starting point: https://reflex.dev/docs/styling/responsive/. But reflex also supports tailwind so that you can use its responsive utilities such as these: https://tailwindcss.com/docs/responsive-design

These should get you started.