How to centre a div on the edge of another div in SASS? code example

Example: center an element on the page with include mixin

/* First we create our mixin with the styles to center the element */
@mixin center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

/* Then we call that mixin in the child element. The position of the parent must be relative */
.parent {
  position: relative;
}

.child {
 @include center; 
}