ant-design/components/button/demo/linear-gradient.tsx

import React, { useContext } from 'react';
import { Button, ConfigProvider, Space } from 'antd';
import { AntDesignOutlined } from '@ant-design/icons';
import { css } from '@emotion/css';

const App: React.FC = () => {
  const { getPrefixCls } = useContext(ConfigProvider.ConfigContext);
  const rootPrefixCls = getPrefixCls();
  const linearGradientButton = css`
    &.${rootPrefixCls}-btn-primary:not([disabled]):not(.${rootPrefixCls}-btn-dangerous) {
      border-width: 0;

      > span {
        position: relative;
      }

      &::before {
        content: '';
        background: linear-gradient(135deg, #6253E1, #04BEFE);
        position: absolute;
        inset: 0;
        opacity: 1;
        transition: all 0.3s;
        border-radius: inherit;
      }

      &:hover::before {
        opacity: 0;
      }
    }
  `;
  return (
    <ConfigProvider
      button={{
        className: linearGradientButton,
      }}
    >
      <Space>
        <Button type="primary" size="large" icon={<AntDesignOutlined />}>
          Gradient Button
        </Button>
        <Button size="large">Button</Button>
      </Space>
    </ConfigProvider>
  );
};

export default App;