diff --git a/components/style/queries/feature.rs b/components/style/queries/feature.rs
index 23a12713baa..c2bfee7db41 100644
--- a/components/style/queries/feature.rs
+++ b/components/style/queries/feature.rs
@@ -8,6 +8,7 @@ use crate::parser::ParserContext;
 use crate::values::computed::{self, CSSPixelLength, Ratio, Resolution};
 use crate::Atom;
 use cssparser::Parser;
+use super::condition::KleeneValue;
 use std::fmt;
 use style_traits::ParseError;
 
@@ -54,7 +55,7 @@ pub enum Evaluator {
         serializer: KeywordSerializer,
         /// The evaluator itself. This is guaranteed to be called with a
         /// keyword that `parser` has produced.
-        evaluator: fn(&computed::Context, Option<KeywordDiscriminant>) -> bool,
+        evaluator: fn(&computed::Context, Option<KeywordDiscriminant>) -> KleeneValue,
     },
 }
 
@@ -84,12 +85,12 @@ macro_rules! keyword_evaluator {
         fn __evaluate(
             context: &$crate::values::computed::Context,
             value: Option<$crate::queries::feature::KeywordDiscriminant>,
-        ) -> bool {
+        ) -> $crate::queries::condition::KleeneValue {
             // This unwrap is ok because the only discriminants that get
             // back to us is the ones that `parse` produces.
             let value: Option<$keyword_type> =
                 value.map(|kw| ::num_traits::cast::FromPrimitive::from_u8(kw).unwrap());
-            $actual_evaluator(context, value)
+            $crate::queries::condition::KleeneValue::from($actual_evaluator(context, value))
         }
 
         $crate::queries::feature::Evaluator::Enumerated {
diff --git a/components/style/queries/feature_expression.rs b/components/style/queries/feature_expression.rs
index c38fecc8c1b..b4715c00739 100644
--- a/components/style/queries/feature_expression.rs
+++ b/components/style/queries/feature_expression.rs
@@ -637,7 +637,7 @@ impl QueryFeatureExpression {
                     .kind
                     .non_ranged_value()
                     .map(|v| *expect!(Enumerated, v));
-                evaluator(context, computed)
+                return evaluator(context, computed)
             },
             Evaluator::BoolInteger(eval) => {
                 let computed = self
diff --git a/components/style/queries/values.rs b/components/style/queries/values.rs
index 5bd1cede48b..f4934408c4d 100644
--- a/components/style/queries/values.rs
+++ b/components/style/queries/values.rs
@@ -4,6 +4,9 @@
 
 //! Common feature values between media and container features.
 
+use app_units::Au;
+use euclid::default::Size2D;
+
 /// The orientation media / container feature.
 /// https://drafts.csswg.org/mediaqueries-5/#orientation
 /// https://drafts.csswg.org/css-contain-3/#orientation
@@ -17,10 +20,7 @@ pub enum Orientation {
 
 impl Orientation {
     /// A helper to evaluate a orientation query given a generic size getter.
-    pub fn eval<T>(size: euclid::default::Size2D<T>, value: Option<Self>) -> bool
-    where
-        T: PartialOrd,
-    {
+    pub fn eval(size: Size2D<Au>, value: Option<Self>) -> bool {
         let query_orientation = match value {
             Some(v) => v,
             None => return true,
diff --git a/components/style/stylesheets/container_rule.rs b/components/style/stylesheets/container_rule.rs
index 3734e73c770..f9d488b9b49 100644
--- a/components/style/stylesheets/container_rule.rs
+++ b/components/style/stylesheets/container_rule.rs
@@ -296,6 +296,12 @@ pub struct ContainerInfo {
     wm: WritingMode,
 }
 
+impl ContainerInfo {
+    fn size(&self) -> Option<Size2D<Au>> {
+        Some(Size2D::new(self.size.width?, self.size.height?))
+    }
+}
+
 fn eval_width(context: &Context) -> Option<CSSPixelLength> {
     let info = context.container_info.as_ref()?;
     Some(CSSPixelLength::new(info.size.width?.to_f32_px()))
@@ -332,12 +338,12 @@ fn eval_aspect_ratio(context: &Context) -> Option<Ratio> {
     ))
 }
 
-fn eval_orientation(context: &Context, value: Option<Orientation>) -> bool {
-    let info = match context.container_info.as_ref() {
-        Some(info) => info,
-        None => return false,
+fn eval_orientation(context: &Context, value: Option<Orientation>) -> KleeneValue {
+    let size = match context.container_info.as_ref().and_then(|info| info.size()) {
+        Some(size) => size,
+        None => return KleeneValue::Unknown,
     };
-    Orientation::eval(info.size, value)
+    KleeneValue::from(Orientation::eval(size, value))
 }
 
 /// https://drafts.csswg.org/css-contain-3/#container-features