html {
    display: table;
    margin: auto;}

body {
    display: table-cell;
    vertical-align: middle;
    background-color: rgb(0,73,83);
    color: aqua;
    line-height: 1.6rem;
    min-height: 100vh;
    width: 60vw;
}

header {
    text-align: center;
    border-radius: 21px 69px;
}

header, section {
    border: 4px solid rgb(0,128,128);
    background-color: black;
}

section {
    border-radius: 21px 69px;    
}

header, section, div {
    padding: 0 1vw;
    margin: 15px 0;
}