<style>
.container {
    height: 120px;
    width: 120px;
    position: relative;
    background-color: green;
}

div div {
	background: blue;
    height: 10px;
}
</style>
<div class=container>
    <div style="width: 12px;"></div>
    <div style="width: 120px;"></div>
</div>