/* elements don't need a "."*/
body {
    color: #f7f7f7;
}

/*classes need a "." */
.jumbotron {
    background-image: url("../images/nasa.jpg");
    background-size: 100% 100%;
    text-align: center;
}

form {
    font-family: inherit; font-size: 1rem;
}

ul {
    font-family: inherit; font-size: 1rem;
}

li {
    font-family: inherit; font-size: 1rem;
}