div { box-sizing: border-box; } .board { width: 84vw; margin: auto; outline: 1px solid black; } .board .field { border: 1px solid black; width: 12vw; height: 12vw; float: left; } .board .row .field:first-child { clear: both; } .board .field .piece { width: 10vw; height: 10vw; border-radius: 50%; margin: 1vw; } .board .field .blue { background-color: blue; } .board .field .red { background-color: red; }