* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  font-size: 62.5%;
  height: 100%;
  width: 100%;
}

body {
  background-color: #f9f9f9;
  color: #333;
  font-family: Arial, sans-serif;
  line-height: 1.6;
}

main {
  margin: 40px auto;
  max-width: 800px;
  padding: 0 20px;
}

header {
  margin-bottom: 40px;
  text-align: center;
}

a {
  color: #0366d6;
  font-weight: bold;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

h1 {
  font-size: 2.4rem;
}

h2 {
  font-size: 2rem;
}

p {
  font-size: 1.6rem;
}

footer {
  color: #777;
  font-size: 1.4rem;
  font-weight: bold;
  margin-top: 60px;
  text-align: center;
}

pre {
  background: #eee;
  font-size: 1.2rem;
  overflow-x: auto;
  padding: 10px;
}