My question is about Chapter 8：《Supporting different screen sizes》：
Click the drop down for First Item and change it from Safe Area to Superview. Also, if the Constant field has a non-zero value, change it to 0.
Do the same for the other three constraints. Note that for two of the constraints, Safe Area will be the Second Item and not the First Item. So change either one based on which one specifies Safe Area.
When i operations iPhone 11 and change this constant to “Superview”，but the screen are not full screen，why：