body {
    background-color: #121212;
    color: #cdcdcd;
    font-family: serif;
    text-align: center;
}

header {
    margin-left: auto;
    margin-right: auto;
    width: 100%;
    max-width: 750px;
    text-align: center;
}

main,
section,
footer {
    margin-left: auto;
    margin-right: auto;
    width: 100%;
    max-width: 750px;
    text-align: left;
}

footer {
    text-align: center;
}

h1 {
    font-size: 32px;
}

h2 {
    font-size: 24px;
}

h3 {
    font-size: 22px;
}

h4 {
    font-size: 18px;
}

h5 {
    font-size: 16px;
}

h6 {
    font-size: 12px;
}

p {
    margin-left: auto;
    margin-right: auto;
    font-size: 20px;
}

footer p {
    font-size: 16px;
}

ul {
    margin-left: auto;
    margin-right: auto;
    max-width: 650px;
}

ul > li {
    text-align: left;
    font-size: 20px;
}

a {
    text-decoration: none;
    color: #63ab3f;
}

a:hover {
    text-decoration: underline;
    color: #85ce5f;
}

header > img,
section > img {
    width: 100%;
    max-width: 700px;
}

code {
    font-size: 14px;
}

.code-block {
    border: 1px solid #bdbdbd;
    background-color: #0f0f0f;
    padding: 5px;
    display: block;
    max-width: 700px;
    text-align: left;
    margin-left: auto;
    margin-right: auto;
    font-size: 14px;
}

#back {
    text-align: center;
}