--- a/servo/components/style/values/specified/align.rs
+++ b/servo/components/style/values/specified/align.rs
@@ -353,19 +353,19 @@ fn parse_normal_or_baseline(input: &mut 
     }
 }
 
 // <content-distribution>
 fn parse_content_distribution(input: &mut Parser) -> Result<AlignFlags, ()> {
     let ident = input.expect_ident()?;
     match_ignore_ascii_case! { &ident,
       "stretch" => Ok(ALIGN_STRETCH),
-      "space-between" => Ok(ALIGN_SPACE_BETWEEN),
-      "space-around" => Ok(ALIGN_SPACE_AROUND),
-      "space-evenly" => Ok(ALIGN_SPACE_EVENLY),
+      "space_between" => Ok(ALIGN_SPACE_BETWEEN),
+      "space_around" => Ok(ALIGN_SPACE_AROUND),
+      "space_evenly" => Ok(ALIGN_SPACE_EVENLY),
       _ => Err(())
     }
 }
 
 // [ <overflow-position>? && <content-position> ]
 fn parse_overflow_content_position(input: &mut Parser) -> Result<AlignFlags, ()> {
     // <content-position> followed by optional <overflow-position>
     if let Ok(mut content) = input.try(|input| parse_content_position(input)) {