ant-design/components/grid/demo/flex-stretch.tsx

import React from 'react';
import { Col, Divider, Row } from 'antd';

const App: React.FC = () => (
  <>
    <Divider orientation="left">Percentage columns</Divider>
    <Row>
      <Col flex={2}>2 / 5</Col>
      <Col flex={3}>3 / 5</Col>
    </Row>
    <Divider orientation="left">Fill rest</Divider>
    <Row>
      <Col flex="100px">100px</Col>
      <Col flex="auto">Fill Rest</Col>
    </Row>
    <Divider orientation="left">Raw flex style</Divider>
    <Row>
      <Col flex="1 1 200px">1 1 200px</Col>
      <Col flex="0 1 300px">0 1 300px</Col>
    </Row>

    <Row wrap={false}>
      <Col flex="none">
        <div style={{ padding: '0 16px' }}>none</div>
      </Col>
      <Col flex="auto">auto with no-wrap</Col>
    </Row>
  </>
);

export default App;