header.html

<style type="text/css">

@import url('https://fonts.googleapis.com/css2?family=Fira+Mono:wght@500&Fira+Sans&family=Roboto+Slab:wght@300&display=swap');

html {
  font-family: "Roboto Slab", serif;
  font-size: 16px;
  max-width: 100%;
}

body {
  color: #444;
  margin-left: 15rem;
  max-width: 40rem;
  padding: .25rem;
}

pre,
code {
  font-family: "Fira Mono", monospace;
}

h1,h2 {
  font-family: "Fira Sans", monospace;
}

pre {
  padding: .5rem;
  line-height: 1.25;
  overflow-x: scroll;
}

a,
a:visited {
  color: #3498db;
}

a:hover,
a:focus,
a:active {
  color: #2980b9;
}

p {
  font-size: 1rem;
  margin-bottom: 1rem;
}

ul {
  padding-left: 1.5rem;
}

h1 {
  font-size: 1.5rem;
}

h1,h2 {
  margin: 0rem -10rem 0rem 1rem;
  margin-left: -10rem;
}

h2 {
  font-size: 1.3rem;
  color: #800000;
  float: left;
}

h3 {
  font-size: 1.2rem;
}

h4 {
  margin: 0 0;
  padding: 0;
}

h5 {
}

h6 {
}

small {
  font-size: .707em;
}

blockquote {
  border-left: 8px solid #fafafa;
  padding: 1rem;
}

pre,
code {
  background-color: #fafafa;
}

dl {
}
dt {
  float: left;
  width: 5rem;
  text-align: right;
  margin-right:0.5em;
}
dt::after {
  content: ": ";
}
dd {
  margin-left: 5.5rem;
}

.footer {
  font-size: .6rem;
  float: right;
}

</style>