body {
    text-align: center;
    font-family: Arial;
    color: gray;
    margin: 0;
}

.top-div {
    padding: 20px 50px 0;
}

.nav {
    float: right;
    text-decoration: none;
    color: gray;
/*     padding-right: 2%; */
}

.nav:hover {
    color: #ccc;
    text-decoration: underline;
}

.main-div {
    margin-top: 30vh;
}

#input {
    width: 60%;
    margin: 5px 0;
}

@media screen and (max-width:600px){
    .heading {
        font-size: 1.5em;
    }
}