wcfsetup/install/files/style/bootstrap/mixin/box.scss

   1 @mixin box($imageSize, $margin: 0) {
   2         display: flex;
   3
   4         > :first-child:not(:last-child) {
   5                 flex: 0 0 auto;
   6                 margin-right: $margin;
   7         }
   8
   9         > :last-child {
  10                 flex: 1 1 auto;
  11                 overflow: hidden;
  12         }
  13 }