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

body {
  font-family: monospace;
  font-size: 16px;
  line-height: 1.6;
  color: #000;
  background: #fff;
  padding: 20px;
}

.container {
  max-width: 600px;
  margin: 0 auto;
}

h1 {
  font-size: 32px;
  margin-bottom: 20px;
}

h2 {
  font-size: 18px;
  margin-top: 30px;
  margin-bottom: 10px;
  text-transform: lowercase;
}

p {
  margin-bottom: 15px;
}

.intro {
  font-size: 18px;
  margin-bottom: 30px;
}

ul {
  margin-left: 20px;
  margin-bottom: 15px;
}

li {
  margin-bottom: 5px;
}

code {
  background: #f0f0f0;
  padding: 2px 6px;
  border: 1px solid #ddd;
}

a {
  color: #000;
  text-decoration: underline;
}

a:hover {
  background: #ff0;
}

em {
  font-style: normal;
  background: #ffeb3b;
  padding: 2px 4px;
}

footer {
  margin-top: 50px;
  padding-top: 30px;
  border-top: 1px solid #000;
  font-size: 14px;
}

footer p {
  margin-bottom: 5px;
}

@media (max-width: 640px) {
  body {
    font-size: 14px;
    padding: 15px;
  }

  h1 {
    font-size: 24px;
  }

  .intro {
    font-size: 16px;
  }
}