freeCodeCamp/client/src/components/layouts/night.css

.night body {
  background-color: #333;
  color: #ddd;
}

.night .btn-invert {
  background-color: #ddd;
  color: #006400;
}

.night .btn-invert:hover,
.night .btn-invert:focus {
  background-color: #006400;
  color: #ddd;
}

.night input,
.night textarea {
  background-color: #ddd;
  color: #333;
}

.night a {
  color: #f8f8f8;
}

.night .table-striped > tbody > tr:nth-child(odd) {
  background-color: #555555;
}

.night .challenge-preview {
  background: #fff;
}
.night .test-result:nth-child(2n + 1) {
  color: #fff;
  background: #2a2a2a;
}

.night .challenge-instructions pre,
.night .challenge-instructions pre code,
.night .challenge-instructions blockquote,
.night blockquote,
.night code,
.night pre {
  background-color: #242424;
  color: #02a902;
}

.night .list-group-item {
  background-color: unset;
}