Edit in JSFiddle

body{margin: 0;padding:0;}
.box{
    margin: 20px auto;
    border: 10px solid black;
    width: 150px;
    height: 150px;
    background-color: gold;
}

.radius{
    border-radius: 50px;
}

.outline{
    outline: 10px solid skyblue;
}

<div class="box radius outline"></div>