How to position absolutely positioned elements vertically and horizontally.
Center horizontally:
.element {
position: absolute;
left: 0;
right: 0;
margin-left: auto;
margin-right: auto;
}
Center horizontally and vertically:
.parent {
position: relative;
}
.child {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}