title: Do I have to write separate UI code for every different os?
body: <p>i am new to xamarin. </p>
  
  <p>1) I wonder if it's possible in xamarin to write single ui code that can be used in all platforms - android, ios, windows. Or do i have to write separete ui code for every platform  ?</p>
  
  <p>2) If it's possible to use single ui code for all platforms, would it be good practice to do so ?</p>