body {
  margin: 0;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: sans-serif;
  color: white;
}

.building {
  background: rgba(0, 0, 0, 0.7);

  padding: 40px;

  border-radius: 12px;

  text-align: center;

  width: 420px;

  box-shadow: 0 0 30px rgba(0, 0, 0, 0.8);
}

.building h1 {
  margin-top: 0;
}

.back {
  display: inline-block;
  margin-top: 20px;
  padding: 12px 20px;

  background: #2c6cff;
  color: white;

  text-decoration: none;
  border-radius: 6px;

  transition: 0.2s;
}

.back:hover {
  background: #4a85ff;
}