diff --git a/components/style/gecko/media_features.rs b/components/style/gecko/media_features.rs
index 7751b8dd162..35d57346034 100644
--- a/components/style/gecko/media_features.rs
+++ b/components/style/gecko/media_features.rs
@@ -126,18 +126,18 @@ fn eval_scan(_: &Context, _: Option<Scan>) -> bool {
 }
 
 /// https://drafts.csswg.org/mediaqueries-4/#color
-fn eval_color(context: &Context) -> u32 {
+fn eval_color(context: &Context) -> i32 {
     unsafe { bindings::Gecko_MediaFeatures_GetColorDepth(context.device().document()) }
 }
 
 /// https://drafts.csswg.org/mediaqueries-4/#color-index
-fn eval_color_index(_: &Context) -> u32 {
+fn eval_color_index(_: &Context) -> i32 {
     // We should return zero if the device does not use a color lookup table.
     0
 }
 
 /// https://drafts.csswg.org/mediaqueries-4/#monochrome
-fn eval_monochrome(context: &Context) -> u32 {
+fn eval_monochrome(context: &Context) -> i32 {
     // For color devices we should return 0.
     unsafe { bindings::Gecko_MediaFeatures_GetMonochromeBitsPerPixel(context.device().document()) }
 }
diff --git a/components/style/queries/feature.rs b/components/style/queries/feature.rs
index c2bfee7db41..3658cb34998 100644
--- a/components/style/queries/feature.rs
+++ b/components/style/queries/feature.rs
@@ -36,7 +36,7 @@ pub type KeywordParser = for<'a, 'i, 't> fn(
 pub enum Evaluator {
     Length(QueryFeatureGetter<CSSPixelLength>),
     OptionalLength(QueryFeatureGetter<Option<CSSPixelLength>>),
-    Integer(QueryFeatureGetter<u32>),
+    Integer(QueryFeatureGetter<i32>),
     Float(QueryFeatureGetter<f32>),
     BoolInteger(QueryFeatureGetter<bool>),
     /// A non-negative number ratio, such as the one from device-pixel-ratio.
diff --git a/components/style/queries/feature_expression.rs b/components/style/queries/feature_expression.rs
index ec0e7f5b113..24a09e5b54c 100644
--- a/components/style/queries/feature_expression.rs
+++ b/components/style/queries/feature_expression.rs
@@ -663,8 +663,8 @@ impl QueryFeatureExpression {
 pub enum QueryExpressionValue {
     /// A length.
     Length(Length),
-    /// A (non-negative) integer.
-    Integer(u32),
+    /// An integer.
+    Integer(i32),
     /// A floating point value.
     Float(CSSFloat),
     /// A boolean value, specified as an integer (i.e., either 0 or 1).
@@ -705,12 +705,12 @@ impl QueryExpressionValue {
     ) -> Result<QueryExpressionValue, ParseError<'i>> {
         Ok(match for_feature.evaluator {
             Evaluator::OptionalLength(..) | Evaluator::Length(..) => {
-                let length = Length::parse_non_negative(context, input)?;
+                let length = Length::parse(context, input)?;
                 QueryExpressionValue::Length(length)
             },
             Evaluator::Integer(..) => {
-                let integer = Integer::parse_non_negative(context, input)?;
-                QueryExpressionValue::Integer(integer.value() as u32)
+                let integer = Integer::parse(context, input)?;
+                QueryExpressionValue::Integer(integer.value())
             },
             Evaluator::BoolInteger(..) => {
                 let integer = Integer::parse_non_negative(context, input)?;