.step {
  display: none;
}
.step.active {
  display: block;
}
#progress-bar {
  width: 100%;
  background: #eee;
  height: 10px;
  margin-bottom: 20px;
}
#progress {
  height: 100%;
  background: #4caf50;
  width: 0%;
  transition: width 0.3s ease;
}