ant-design/components/affix/style/index.tsx

import type { CSSObject } from '@ant-design/cssinjs';
import type { FullToken, GenerateStyle } from '../../theme';
import { genComponentStyleHook, mergeToken } from '../../theme';

interface AffixToken extends FullToken<'Affix'> {
  zIndexPopup: number;
}

// ============================== Shared ==============================
const genSharedAffixStyle: GenerateStyle<AffixToken> = (token): CSSObject => {
  const { componentCls } = token;

  return {
    [componentCls]: {
      position: 'fixed',
      zIndex: token.zIndexPopup,
    },
  };
};

// ============================== Export ==============================
export default genComponentStyleHook('Affix', (token) => {
  const affixToken = mergeToken<AffixToken>(token, {
    zIndexPopup: token.zIndexBase + 10,
  });
  return [genSharedAffixStyle(affixToken)];
});