In order to configure the browser compatibility for your app, you will need to edit the /quasar.config file:

build: {
  target: {
    browser: 'baseline-widely-available',
    node: 'node22'
  }
}

Based on the Quasar Mode that you will be using (SPA/SSR/PWA/Electron/… etc) you will have client-side files (that run in the browser) and possibly Node.js running files. This is what the two keys of target Object above are for.

Furthermore, based on your /postcss.config.js file content, your CSS will also pass through autoprefixer for which you can configure the browser levels that you are interested in:

autoprefixer({
  overrideBrowserslist: [
    'last 4 Chrome versions',
    'last 4 Firefox versions',
    'last 4 Edge versions',
    'last 4 Safari versions',
    'last 4 Android versions',
    'last 4 ChromeAndroid versions',
    'last 4 FirefoxAndroid versions',
    'last 4 iOS versions'
  ]
})

More info on how to specify autoprefixer browser ranges: browserslist.