<style>
.box {
width: 300px;
border: 1px solid #aaa;
border-radius: 2px;
box-shadow: 2px 2px 8px rgba(0,0,0,0.1);
padding: 1em;
margin: 0 0 1em 0;
}
</style>
<div class="box">
<slot></slot>
</div>