given WeWeb apps might have PWA support,
Can we have WeWeb.io webapps with responsive UI even today? How can we do it?
I found this Add a responsive content property | weweb.io developer documentation
So for a page to be responsive, every element of it has to be responsive? or it is something set at page or in best case at app level?
It is super easy to build responsive apps in weweb. Weweb follows the CSS principles so you start designing your app for desktop and then you gradually go down to smaller screen sizes by using the breakpoint buttons.
Any changes you make on the tablet breakpoints will be visible only on that size and below. Same for the mobile breakpoint.
Here is a great video by @Joyce on this topic: https://youtu.be/-5f1vsxgtx0
The link you provided is from the developer documentation. This is the way to go when you are developping your own components.
All existing Weweb already implement this feature for the appropriate properties (width for example, or layout of the container). Slavo pointed you the way to use it for all existing components :).