.child { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); }
position: absolute; margin-left: auto; margin-right: auto; left: 0; right: 0; text-align: center;
top: "50%", left: "50%", transform: "translate(-50%, -50%)"
position: absolute; margin-left: auto; margin-right: auto; left: 0; right: 0;