SOURCE

<div class="container">
    <div class="item">1-div</div>
    <span class="span-item">2-span</span>
</div>

.container {
    background-color: orange;
    height: 500px;
    width: 400px;
}
.item {
    background-color: skyblue;
    height: 100px;
    width:100px;
    /* transform: translateX(50%) */
    /* margin: 0 auto; */
}
.span-item {
    background-color: orchid;
}