-moz-justify-content: center css code example

Example 1: center with css

.parent {
  position: relative;
}
.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

Example 2: centering css elements

// add to the parent element
.parent {
	display: grid;
    place-items: center;
}