style/react-tabs.scss (46 lines of code) (raw):
.react-tabs {
  -webkit-tap-highlight-color: transparent;
  &__tab-list {
    border-bottom: 1px solid #aaa;
    margin: 0 0 10px;
    padding: 0;
  }
  &__tab {
    display: inline-block;
    border: 1px solid transparent;
    border-bottom: none;
    bottom: -1px;
    position: relative;
    list-style: none;
    padding: 6px 12px;
    cursor: pointer;
    &--selected {
      background: #fff;
      border-color: #aaa;
      color: black;
      border-radius: 5px 5px 0 0;
    }
    &--disabled {
      color: GrayText;
      cursor: default;
    }
    &:focus {
      outline: none;
      &:after {
        content: "";
        position: absolute;
        height: 5px;
        left: -4px;
        right: -4px;
        bottom: -5px;
        background: #fff;
      }
    }
  }
  &__tab-panel {
    display: none;
    &--selected {
      display: block;
    }
  }
}