jtBaseApp/node_modules/vant/lib/tab/index.less

.van-tab {
  &__panel {
    &,
    &-wrapper {
      flex-shrink: 0;
      box-sizing: border-box;
      width: 100%;
    }

    &-wrapper--inactive {
      height: 0;
      overflow: visible;
    }
  }
}