myapp.css

*{
    -webkit-user-select: none; user-select: none;
}
body {
    margin:0; padding:0;
    font-family: Sans-Serif;
    background-color: black;
}
header,footer {
    margin: 0; padding: 0;
    background-color: black; color: white;
    text-align: center;
}
header{     height: 2rem; }
footer{     height: 1rem; }
header > h1 {
    margin: 0; padding: 0;
    font-size: 1.5rem;  line-height: 1.8rem;
}
footer > p {
    margin: 0; padding: 0;
    font-size: 0.6rem;  line-height: 0.9rem;
}
main{
    margin: 0; padding: 0.8rem;
    height: calc(100vh - 4.8rem);
    background-color: white; color: black;
}