This isn't exactly a bug, but I feel the behavior is highly unexpected. let _style = css!(" display: flex; flex-direction: column; ... "); formats to let _style = css!( " display: flex; flex-direction: column; ... " ); I much prefer the original code. Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=2e601d5bbc9f0103bf217f469c6dc0a1