<style> #box-container { height: 500px; display: flex; } #box-1 { background-color: dodgerblue; width: 50%; height: 50%; } #box-2 { background-color: orangered; width: 50%; height: 50%; } </style> <div id="box-container"> <div id="box-1"></div> <div id="box-2"></div> </div>