> so it can't gracefully scale layouts down from desktop to mobile sizes (when you have a 3-column layout you have lots of control over column widths, but no way of turning them into 3 rows instead).
On Apple platforms (UIKit on iOS) handling such layout changes is done with another mechanism on top of auto layout. Something they call "Size Classes". You get a callback saying eg. "view has changed to Regular width, Compact height" and you switch to a another set of auto-layout constraints + animate as desired.
This size class system is used for stuff like handling rotation on the iPhone and transitioning to split-screen mode on iPad.
On Apple platforms (UIKit on iOS) handling such layout changes is done with another mechanism on top of auto layout. Something they call "Size Classes". You get a callback saying eg. "view has changed to Regular width, Compact height" and you switch to a another set of auto-layout constraints + animate as desired. This size class system is used for stuff like handling rotation on the iPhone and transitioning to split-screen mode on iPad.