Stamp border

<div class="container">
<!-- Inner -->
<div class="container__inner">
<!-- Content -->
...
</div>
</div>
.container {
/* Background */
background-color: #ccc;
background-image: radial-gradient(#fff 50%, transparent 50%);
background-position: -5px -5px;
background-repeat: repeat;
background-size: 10px 10px;
/* Spacing */
padding: 5px;
}
.container__inner {
/* Background */
background-color: #ccc;
}