let { code, map } = transform({
    filename: 'test.css',
    minify: true,
    code: new TextEncoder().encode('.foo{color: red;@light {color: green;}; @dark {color:yellow;}}'),
    customAtRules: {
        light: {
            prelude: null,
            body: 'style-block'
        },
        dark: {
            prelude: null,
            body: 'style-block'
        }
    },
    visitor: composeVisitors([{
        Rule: {
            custom: {
                light({ body, loc }) {
                    return {
                        type: 'media',
                        value: {
                            rules: body.value,
                            loc,
                            query: {
                                mediaQueries: [
                                    {
                                        raw: '(prefers-color-scheme: light)'
                                    }
                                ]
                            }
                        }
                    }
                },
            }
        }
    },
    {
        Rule: {
            custom: {
                dark({ body, loc }) {
                    return {
                        type: 'media',
                        value: {
                            rules: body.value,
                            loc,
                            query: {
                                mediaQueries: [
                                    {
                                        raw: '(prefers-color-scheme: dark)'
                                    }
                                ]
                            }
                        }
                    }
                },
            }
        }
    }]),
});