how to position an element in horizontal center css code example

Example 1: center div horizontally and vertically

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

Example 2: centering horizontally

div.center{display:block;margin:auto;width:50%;}
p.center{text-align:center;}