Unexpected Warning: rules skipped due to selector errors about critters HOT 4 CLOSED

import Critters from 'critters';

const critters = new Critters();
critters.readFile = f => assets[f];
const assets = {
  '/x.css': `
    @import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap');
    .foo{ color:red; }
  `
};

const html = await critters.process(`<div class="foo">hi</div><link rel="stylesheet" href="/x.css">`);

console.log(html);
"... <div class="foo">hi</div><style>@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap');.foo{color:red}</style>  ..."