Is this this the only CSS you'll ever need?

body {
    margin: 40px auto;
    padding: 0 10px;
    max-width: 66ch;
    line-height: 1.6;
    font-size: 18px;
    color: #ccc;
    background: #234;
}

h1,
h2,
h3 {
    line-height: 1.2;
}

a {
    color: #abf;
}