body{font-family:Arial,sans-serif;padding:20px}.content{display:none}.content.active{display:block}button{margin-top:5px;padding:5px 10px;border:0;background-color:#4caf50;color:white;font-size:13px;border-radius:5px;cursor:pointer;transition:background-color .3s}button:hover{background-color:#45a049}