frontend/config-overrides.js

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

module.exports = override(
	addLessLoader({
		// If you are using less-loader@5 or older version, please spread the lessOptions to options directly.
		lessOptions: {
			javascriptEnabled: true,
			modifyVars: { '@base-color': '#CB1B45', '@body-bg': '#bad3e9' },
		},
	}),
);