I have an app developed for desktop. Now the customer is asking for mobile responsive. Is there any easy way to build mobile pages from existing desktop pages?
Thanks in advance.
Best way to do this is to create phone specific layouts and then change your desktop pages to phone specific pages.
However, if you want it to be responsive (which is the best practice for all designs since you do not know the size of device your user group may be using, then make sure you use layout grids and containers to build these pages and use Bootstrap helpers like you will fine here https://www.w3schools.com/bootstrap/bootstrap_grid_examples.asp
If you need any more help, let me know