body {
    background-color: black;
    color: white;
}
header {
    background-color: green;
    width: 100%;
    height: 5vh;
    position: relative;
    left: 0px;
    top: 0px;
}
header a {
    position: relative;
    padding-left: 1vw;
    padding-right: 1vw;
    top: 1vh;
    font-family: sans-serif;
    text-decoration: none;
}
.H1 {
    font-size: 1rem;
}
.H2 {
    font-size: .95rem;
}
.H3 {
    font-size: .90rem;
}
.H4 {
    font-size: .85rem;
}
.H5 {
    font-size: .80rem;
}
.H6 {
    font-size: .75rem;
}