[devote]

<style>
    div {
        position: absolute;
        z-index: 100;
        left: 50%;
        top: 50%;
        margin: -50px 0 0 -50px;
        width: 100px;
        height: 100px;

        border: 1px solid #000;
    }
</style>
<div>ololo</div>