html,
body {
  font: 100% sans-serif;
  height: 100%;
}
body {
  margin: 0;
  color: #333;
}

.body-container {
  max-width: 56.250em; /* 900px */
}

.form-container {
  width: 37.500em; /* 600px */
}
.form-container .form-group {
  margin: 1rem 0;
}