body{
    padding:0;
    margin:0;
    display:flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #ecf0f3;
}
.container
{
    width:45%;
    height: 45vh;;
    padding:10px;
    border-radius: 8px;
    box-shadow: 12px 12px 20px #cbced1,
                -12px -12px 20px #ffffff;
}

.display #screen{
    width:97%;
    height:70px;
    font-size: 35px;
    outline:none;
    border:none;
    text-align: right;
    padding-right: .5em;
    background: #ecf0f3;
    border-radius: 6px;
    box-shadow: inset 8px 8px 8px #cbced1,
                inset -8px -8px 8px #ffffff;

}
.btns{
    width:100%;
    margin-top:1.7em;
    display:flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}
.btns .row button{
    width: 80px;
    height:30px;
    font-size:16px;
    border:none;
    outline:none;
    margin:5px;
    border-radius: 4px;
    box-shadow: 5px 5px 8px #00000020,
                -5px -5px 8px #ffffff;
                transition: .1s;
}
.btns .row button:hover{
    box-shadow: inset 5px 5px 8px rgba(16,16,16,.1),
                inset -5px -5px 8px #fff;
                background:#fff;
            
}
#eval{
    background-color: blue;
    color:#fff;
    box-shadow: inset 5px 5px 8px #66d9ff,
    inset -5px -5px 8px #00ace6;

}
#eval:hover{
    box-shadow: inset 5px 5px 8px #00ace6,
    inset -5px -5px 8px #00ace6;

}
#ac{
    background-color: green;
    color:#fff;


}
#ac:hover{
    box-shadow: inset 5px 5px 8px #2eb82e,
    inset -5px -5px 8px #33cc33;

}
#ce{
    background-color: #ff3399;
    color:#fff;


}
#ce:hover{
    box-shadow: inset 5px 5px 8px #e60073,
    inset -5px -5px 8px #ff3399;

}