pub trait CssWriter {
// Required methods
fn write_space(&mut self) -> Result;
fn write_newline(&mut self) -> Result;
fn write_raw(&mut self, span: Option<Span>, text: &str) -> Result;
fn write_str(&mut self, span: Span, s: &str) -> Result;
fn increase_indent(&mut self);
fn decrease_indent(&mut self);
}