.calsi{

    width:350px;
    height: 500px;
    background-color:black;
    border-radius : 50px;
    display:flex;
    flex-wrap:wrap;
    margin-left:auto;
    margin-right:auto;
    margin-top:50px;





    }
    h1{

    color:white;
    padding:8px;
    

    }
    #display{

    width:45px;
    height:45px;
    width:100%;

    border-radius:20px;
    border:0;
    margin:10px;







    }

    #btn
    {

    width:40px;
    height:50px;
    border-radius:40%;
    border:0;
    margin:10px;
    
    background-color:orange;
    color:white;


    }
    body{

    background-color:aqua;


    }