body {
  margin: 0.5rem;
  line-height: 1.5rem;
  color: #111;
  background-color: #eee;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
}

header {
  margin-bottom: 1.5rem;
}

header > section > img {
  width: 40rem;
}

header > section > p > span {
  font-weight: bold;
}

main > section {
  margin: 2rem 0;
}

main > section > div {
  display: flex;
}

main > section > div > pre {
  padding: 1rem;
  min-width: 30rem;
  width: 33%;
  border: 1px solid #ccc;
  border-radius: 1rem 0 0 1rem;
  font-family: monospace;
}

main > section > div > button {
  margin: 0;
  width: 2rem;
  border: 1px solid #ccc;
  border-left: 0;
  border-radius: 0 1rem 1rem 0;
  background-color: #ccc;
}

main > section > div > button:hover {
  background-color: #bbb;
}

main > section > div > button > img {
  width: 1rem;
}

aside {
  display: none;
  position: fixed;
  top: 75%;
  left: 50%;
  width: 15rem;
  margin-left: -7.5rem;
  padding: 1rem;
  align-items: center;
  justify-content: center;
  border-radius: 1rem;
  background-color: #ddd;
}

aside.visible {
  display: flex;
  opacity: 1;
  animation: -fade;
  animation-duration: 3s;
}

@keyframes -fade {
  0% {
    opacity: 1;
  }
  33% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}

footer {
  margin-top: 1.5rem;
}

footer > div:first-of-type {
  margin-bottom: 1rem;
}

footer > div:last-of-type > a > img {
  width: 30rem;
}

h1, h2 {
  margin-bottom: 1rem;
  line-height: 2.5rem;
  font-weight: bold;
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.25rem;
}