body {
    max-width: 650px;
    margin: 40px auto;
    padding: 0 10px;
    font: 18px/1.5 -apple-system, BlinkMacSystemFont, "avenir next", avenir, "Segoe UI", "lucida grande", "helvetica neue", helvetica, "Fira Sans", roboto, noto, "Droid Sans", cantarell, oxygen, ubuntu, "franklin gothic medium", "century gothic", "Liberation Sans", sans-serif;
    color: #444
}

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