Sample (in no way perfect!) CSS for learnr tutorials with dark background

learnr-dark.css

body {
	font-size: 16px;
}
.topicsList .topic {
    font-size: 18px;
}
p.caption {
   font-size: 0.6em;
}

.pageContent {
  background: #002b36;
}

body {
  color: #93a1a1;
}

.btn-default {
  background: ##217ebd;
  color: #93a1a1;
}

.topicsList .topic.current {
  background-color: ##217ebd;
}

.btn-primary{
  color: white;
  background-color: #1f7ab7;
}

.tutorial-question {
  background: #002b36;
}

pre {
  font-size: 22px;
}

.topicsList .topic {
  border-bottom: 1px solid #002b36;
}


h3 {
  font-weight: 500;
}

.ace-tm {
  background-color: #002b36;
  color: #93a1a1;
}

Style Attribute {
  color: rgb(147, 161, 161);
}

Thanks @mine-cetinkaya-rundel. I created it in the learn repo.