config-overrides.js

const {
   override,
   fixBabelImports,
   addLessLoader
} = require('customize-cra');

module.exports = override(
   fixBabelImports('import', {
      libraryName: 'antd',
      libraryDirectory: 'es',
      style: true,
   }),
   addLessLoader({
      javascriptEnabled: true,
      modifyVars: {
         '@primary-color': '#CACE40',
         '@layout-header-background': '#404041',
         '@layout-trigger-background': '#343434;',
         'menu-dark-submenu-bg': '#343434'
      },
   }),
);