.ultra-fast {
  padding: 10px 20px;
  background-color: #34495e;
  color: white;
  border: none;
  border-radius: 4px;
  transition-duration: 0.1s;
  transition-property: background-color;
  cursor: pointer;
  display: inline-block;
  margin: 5px;
}

.ultra-fast:hover {
  background-color: #2c3e50;
}