body {
  font-family: system-ui, sans-serif;
  margin: 0;
  padding: 0;
  background: white;
  color: black;
}
header, footer {
  background: white;
  padding: 1em;
  text-align: center;
}
nav a {
  margin: 0 1em;
  color: #426d4d;
  text-decoration: none;
}
a {
  color: #426d4d
}
a:visited {
  color: #123524;
}
main {
  max-width: 650px;
  margin: 2em auto;
  background: white;
  padding: 2em;
  border-radius: 0.5em;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}