style.css

html {
  background: aliceblue;
}
body {
  min-height: 100vh;
  width: 80%;
  margin: 0 auto;
  background: #fff;
  font-family: Helvetica;
}
#heading {
  border-bottom: 2px solid #2f2e2f;
  background: #999;
}
#navigation {
  border-top: 2px solid #2f2e2f;
  margin-top: -4px;
}
#navigation ul {
  display: flex;
  justify-content: space-around;
  padding: 0;
}
#navigation ul li {
  list-style-type: none;
}
h1 {
  background: #2f2e2f;
  color: #fff;
  padding: 0.5em;
  font-family: Georgia;
}
h1 a {
  text-decoration: none;
  color: #fff;
}
img {
  width: 100%;
}
#wrapper {
  display: flex;
  flex: 1;
}
#content {
  padding: 1em;
  flex: 1;
}
#sidebar {
  background: #e6c2ba;
  color: #333;
  flex: 0 0 12em;
  margin: 1em;
  padding-left: 0.5em;
}
#footer {
  background: #999;
  color: #fff;
  padding: 2em;
}
/* taken from online.theironyard.com */
code {
  background-color: #e3e7e9;
  border-radius: 4px;
  color: #202f37;
  display: inline-block;
  font-family: "source-code-pro", monaco, Consolas, "Lucida Console", monospace, sans-serif;
  font-size: 0.875rem;
  line-height: 1.5;
  padding: 0.125rem 0.25rem;
}
pre {
  background: #999;
  color: #fff;
  padding: 1em;
}