body {
  background-color: #ccc;
  margin: 0;
  padding: 0;
}

main {
  background-color: #fff;
  margin: auto;
  padding: 0 10px;
  width: 690px;
}

header, footer {
  text-align: center;
}

header {
  border-bottom: 2px solid #ccc;
}

footer {
  border-top: 2px solid #ccc;
}

h1, footer p {
  margin: 0;
  padding: 10px 0;
}

a {
  border-bottom: 1px solid #00c;
  color: #00c;
  text-decoration: none;
}

.invisible {
  display: none;
}

input[type=text] {
  box-sizing: border-box;
  line-height: 2em;
  width: 100%;
}

textarea {
  height: 50vh;
  box-sizing: border-box;
  width: 100%;
}

#output-area {
  background-color: #eee;
  padding: 2px;
}