diff --git a/components/style/properties/shorthand/position.mako.rs b/components/style/properties/shorthand/position.mako.rs
index 46d27aa3691..e49c39bc7b8 100644
--- a/components/style/properties/shorthand/position.mako.rs
+++ b/components/style/properties/shorthand/position.mako.rs
@@ -252,7 +252,6 @@
                                        -> Result<(GridTemplateComponent,
                                                   GridTemplateComponent,
                                                   Either<TemplateAreas, None_>), ParseError<'i>> {
-
         // Other shorthand sub properties also parse `none` and `subgrid` keywords and this
         // shorthand should know after these keywords there is nothing to parse. Otherwise it
         // gets confused and rejects the sub properties that contains `none` or `subgrid`.
diff --git a/components/style/values/generics/grid.rs b/components/style/values/generics/grid.rs
index 5c98d5c33dc..b50fb2cf403 100644
--- a/components/style/values/generics/grid.rs
+++ b/components/style/values/generics/grid.rs
@@ -354,8 +354,13 @@ pub enum RepeatCount {
 
 impl Parse for RepeatCount {
     fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
-        if let Ok(i) = input.try(|i| Integer::parse(context, i)) {
+        // Maximum number of repeat is 10000. The greater numbers should be clamped.
+        const MAX_LINE: i32 = 10000;
+        if let Ok(mut i) = input.try(|i| Integer::parse(context, i)) {
             if i.value() > 0 {
+                if i.value() > MAX_LINE {
+                    i = Integer::new(MAX_LINE);
+                }
                 Ok(RepeatCount::Number(i))
             } else {
                 Err(StyleParseError::UnspecifiedError.into())