.option-tab {
  text-align: center;
  height: 30px;
  margin-bottom: 30px;
}

.option-tab .tab {
  display: inline-block;
  font-size: 18px;
  color: rgba(51, 51, 51, 1);
  line-height: 30px;
  float: left;
  margin: 0 30px;
  position: relative;
  cursor: pointer;
}
.option-tab .tab.on{
  color: #2063FF;
}

.option-tab .tab.on:after {
  content: '';
  position: absolute;
  height: 2px;
  background: #2063FF;
  left: 0;
  right: 0;
  bottom: 0;
}