html {
    color: #d5d5d5;
    background-color: #2d2d2d;
    font-family: 'Rubik', sans-serif;
    font-size: 1.1em;
    line-height: 1.5em;
}
body {
    max-width: 75em;
    padding: 0 1em;
    margin: 0 auto;
}
pre {
    display: block;
}
a {
    color: #d5d5d5;
}
a:visited {
    color: #d5d5d5;
}
h1 {
    font-size: 3em;
    color: #d9d9d9;
}
h2 {
    font-size: 2em;
    color: #d9d9d9;
}
h3 {
    font-size: 1.5em;
    text-align: center;
    margin-bottom: 0.5em;
    margin-top: 1.2em;
    color: #d9d9d9;
}
h4 {
    text-align: center;
    max-width: 40em;
    margin: 0 auto;
    font-weight: normal;
    font-size: 1.3em;
    color: #d9d9d9;
}
p {
    line-height: 1.175em;
}
header {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
}
header div {
    display: flex;
}
header div a {
    margin: 0em 1em;
    font-size: 1.75em;
    text-decoration: none;
    font-weight: bold;
}