z-index values are getting flattened to 1 or 2. Does anyone know which of css-loader, style-loader, sass-loader, and postcss-loader could be responsible for this? about shopify-packer HOT 2 CLOSED

module.exports = {
  plugins: [
    require("postcss-preset-env"),
    require("cssnano")({
      preset: [
        "advanced",
        {
          zindex: false,
        },
      ],
    }),
  ],
};