<div class="box"> <div class="blue"></div> <div class="yellow"></div> <div class="red"></div> </div>
* { margin: 0; padding: 0; } .box { width: 100%; height: 300px; background-color: green; } .blue { width: 50px; height: 100px; background-color: blue; } .yellow { width: 100px; height: 50px; background-color: yellow; } .red { width: 80px; height: 80px; background-color: red; }