body {
  background: #111;
  color: #eee;
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 20px;
}

h1 {
  margin-bottom: 10px;
}

.char-tabs {
  margin: 10px 0;
}

.char-tabs button {
  margin-right: 5px;
  padding: 6px 12px;
  background: #222;
  color: #eee;
  border: 1px solid #444;
  cursor: pointer;
}

.char-tabs button.active {
  background: yellow;
  color: black;
}

.run {
  margin: 5px 0;
}