.code-bg {
  flex: 0 1 415px;
  background-size: cover;
  background-image: url('/img/bg-code.jpg');
  border-top-left-radius: 4px;
  border-bottom-left-radius: 4px;
  border: 1px solid #ffffffcc;
  border-right: none;
  transition: flex 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

#screen-wrapper.welcome .code-bg {
  flex: 0 1 480px;
}

#screen-wrapper.summary .code-bg {
  display: none;
}

#tracker {
  float: right;
  padding: 40px 30px;
  background-color: #eeeeeeee;
  width: 250px;
  height: 100%;
  border-left: 1px solid #00000030;
  transition: opacity 0.2s ease;
}

#screen-wrapper.welcome #tracker {
  opacity: 0;
}

#screen-wrapper.summary #tracker {
  opacity: 0;
  width: 0;
  padding: 0;
}

.tracker-step {
  display: flex;
  align-items: center;
  position: relative;
  /* allow absolute children */
}

.tracker-step .number {
  width: 25px;
  height: 25px;
  border-radius: 50%;
  border: 1px solid #777;
  color: #777;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  margin-right: 10px;
  font-size: 14px;
  transition: background-color 0.2s ease, color 0.2s ease, border 0.2s ease;
}

.tracker-step.active .number {
  background-color: #000;
  color: #fff;
  border: none;
}

.tracker-step.done .number {
  background-color: #00000099;
  color: #fff;
  border: none;
}

.tracker-step .label {
  font-size: 17px;
  font-weight: bold;
  color: #777;
  transition: color 0.2s ease;
}

.tracker-step.active .label {
  font-size: 17px;
  font-weight: bold;
  color: #000;
}

.tracker-line {
  position: relative;
  margin: 10px 0;
  margin-left: 12px;
  width: 2px;
  height: 50px;
  background-color: #00000055;
  overflow: hidden;
}

.tracker-line::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 0;
  background-color: #00000077;
  transition: height 0.2s ease-in-out;
}

.tracker-line.done::after {
  height: 100%;
}