*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    background-color: #e9e9e9;
    font-family: monospace,sans-serif;
    font-size: 20px
}    

body{
    height:100vh;
    width:100vw;
    display:flex;
    align-items:center;
    justify-content:center;
    background-image:url(heli on sun.png);
    background-position: center;
    background-size: cover;
}
h1{
margin-left:35%;
}


main{
    padding:2rem;
    border-radius:30px

}

input{
    width:320px;
    height:60px;
    padding: 16px 32px;
    text-align: right;
    border-radius:30px;
    text-shadow: -1px -1px 2px #fff, 2px 2-x 2px rgba(#000, 0.4);
}
.keys {
    display: grid;
    grid-template-columns: repeat(4,1fr /*(fractional unit*/);
    grid-gap: 0.8rem;
    margin-top: 20px
}
button{
    width: 60px;
    height:60px;
    border:none;
    border-radius: 30px;
    cursor:pointer;
    background: #000;

}
#op_key,
#eq_key {
    color: orange;
}
#num_key, #dot{
    color: #e9e9e9;
}