<div class="doubledborder">Double border</div>
<div class="doubledborder2">Double border</div>
.doubledborder {
    background: #3D3D3d;
    color: #FFF;
    font-family: sans-serif;
    padding: 20px;
    margin-bottom: 30px;
    border:10px solid #AFC440;
    outline:5px solid #285769;
}

.doubledborder2 {
    background: #ACB6BA;
    font-family: sans-serif;
    padding: 20px;
    border:5px solid #FFF;
    outline:5px solid #ACB6BA;
}
Rerun