To make UI more powerful move all the UI related dimensions to the separate file.

like if you want to give the height of 20 to SizedBox then we should implement that dimension in that new file named dimensions.dart as

SizedBoxHeightSmall  = 10;
SizedBoxHeightMedium  = 20;
SizedBoxHeightHuge  = 30;

and give that dimension in our file by importing the dimensions file like.

const SizedBox(
  height = SizedBoxHeightMedium,
);

and so on for mediaQuery for making device independent screens too...