CSS support in html macro

[schiegl]

First of thank you for this project! I think a good addition to this project would be CSS support in the <style> tag in the html macro.

The use case would be scoped CSS. Here is an example:

html! {
    div {
        style scoped {            
                /* some css */
        }
        /* some html */
    }
}

In case others are interested, this is my workaround currently:

html! {
    div {
        style scoped {
            r#"
                /* some css */
            "#
        }
        /* some html */
    }
}