SOURCE

<div class="content">
	<div class="box1">
		<div class="box2"></div>
	</div>
</div>

.content {
    border: 1px solid white;
    width: 450px;
    height: 450px;
    background: #111;
}

.box1 {
    height: 300px;
    width: 150px;
    background: pink;
}

.box2 {
    background: green;
    height: 100px;
    width: 100px;
    margin-top: 30px;
}