body{
    display: flex;
    justify-content: center;
}
.main{
    display: flex;
    flex-wrap: wrap;
    position: fixed;
    margin-top: 250px;
    align-items: center;
    border: 2px solid gray;
    border-radius: 10px;
    padding: 5px;
    background-color: lightgreen;
    box-shadow: -3px 3px;
    width: 300px;
}
.output{
    display: flex;
    flex-wrap: wrap;
    width: 100%;
    height: 100px;
    border: 2px solid darkgray;
    border-radius: 10px;
    padding: 4px;
    background-color: white;
    justify-content: flex-end;
    box-shadow:inset -3px 3px;
}
.num{
    width: 21%;
    margin: 2%;
}
.num#del{
    width: 100%;
}
.num:hover{
    box-shadow: inset -2px 2px;
}