*{
    margin: 0;
    padding: 0;
}
#container{
    width:400px;
    border: 2px solid black;
    border-radius: 5px;
    margin: 50px auto;
    font-family: Arial, Helvetica, sans-serif;
}
h1{
    text-align: center;
}
#screen{
    display: block;
    font-size: 2rem;
    margin: 5px auto;
}
#screen:focus{
    outline: none;
}
table{
    margin: 0px auto;
    border: 8px solid lightgray;
}
td{
    height: 60px;
    width: 80px;
    border: 2px solid gray;
    border-radius: 8px;
    box-shadow: 1px 1px 2px rgb(104,104,104);
    transition: 80ms;
}
td:active{
    transform: scale(0.85);
}
button{
    height:100%;
    width:100%;
    font-size: 2rem;
    border-radius: 8px;
    border: 0.1px solid white;
}
button:hover{
    cursor: pointer;
}