const Item = {
  name: "Item",
  data() {
    return {};
  },
  render() {
    console.log(this.$slots);
    return (
      <div>
        <div style="font-size: 20px">1:{this.$slots.title}</div>
        <div>2:{this.$slots.default}</div>
      </div>
    );
  }
};

const Wrapper = {
  name: "Wrapper",
  data() {
    return {};
  },
  render() {
    return (
      <div>
        ----correct:-----------------------------
        <Item>
          <div>content</div>
          <div slot="title">title</div>
        </Item>
        ----incorrect:-----------------------------
        <StyledItem>
          <div>content</div>
          <div slot="title">title</div>
        </StyledItem>
      </div>
    );
  }
};

const StyledItem = styled(Item)`
  color: red;
`;