not showing anything ,

[yuyang-ok]

I am new to this project and new to front end development.
I maybe make some stupid mistaken.
I use allotment kind of this.

import { Allotment } from 'allotment';
import 'allotment/dist/style.css';


 <Allotment defaultSizes={[200, 700]} vertical={false}>
      <div
        style={{ backgroundColor: 'red', minHeight: '100vh', height: '100vh' }}
      >
        1111
        <Left></Left>
      </div>
      <div style={{ backgroundColor: 'blue', minHeight: '100vh' }}>
        1222222
        <TabsWithContent
          handleClose={(index: number) => {
            let id = tabs[index].id;
            setTabs((prevTabs) => prevTabs.filter((x) => x.id !== id));
            if (selectIndex >= index && selectIndex > 0) {
              setSelectIndex(selectIndex - 1);
            }
          }}
          tabs={tabs}
          selectIndex={selectIndex}
          changeTab={(index) => {
            setSelectIndex(index as number);
          }}
          setTabs={setTabs}
        ></TabsWithContent>
      </div>
    </Allotment>

but nothing shows on the screen.

why???