diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 8f4fcaec5c9..bf7bc9aceec 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -3177,7 +3177,6 @@ fn static_assert() {
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_CONTENT;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_SIZE;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_LAYOUT;
-        use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_STYLE;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_PAINT;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_ALL_BITS;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_CONTENT_BITS;
@@ -3201,9 +3200,6 @@ fn static_assert() {
         if v.contains(SpecifiedValue::LAYOUT) {
             bitfield |= NS_STYLE_CONTAIN_LAYOUT;
         }
-        if v.contains(SpecifiedValue::STYLE) {
-            bitfield |= NS_STYLE_CONTAIN_STYLE;
-        }
         if v.contains(SpecifiedValue::PAINT) {
             bitfield |= NS_STYLE_CONTAIN_PAINT;
         }
@@ -3219,7 +3215,6 @@ fn static_assert() {
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_CONTENT;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_SIZE;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_LAYOUT;
-        use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_STYLE;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_PAINT;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_ALL_BITS;
         use crate::gecko_bindings::structs::NS_STYLE_CONTAIN_CONTENT_BITS;
@@ -3249,9 +3244,6 @@ fn static_assert() {
         if gecko_flags & (NS_STYLE_CONTAIN_LAYOUT as u8) != 0 {
             servo_flags.insert(SpecifiedValue::LAYOUT);
         }
-        if gecko_flags & (NS_STYLE_CONTAIN_STYLE as u8) != 0 {
-            servo_flags.insert(SpecifiedValue::STYLE);
-        }
         if gecko_flags & (NS_STYLE_CONTAIN_PAINT as u8) != 0 {
             servo_flags.insert(SpecifiedValue::PAINT);
         }
diff --git a/components/style/values/specified/box.rs b/components/style/values/specified/box.rs
index 2495cca3d6c..d4b66e42ab9 100644
--- a/components/style/values/specified/box.rs
+++ b/components/style/values/specified/box.rs
@@ -752,25 +752,23 @@ pub fn assert_touch_action_matches() {
 
 bitflags! {
     #[derive(MallocSizeOf, SpecifiedValueInfo, ToComputedValue)]
-    #[value_info(other_values = "none,strict,content,size,layout,style,paint")]
+    #[value_info(other_values = "none,strict,content,size,layout,paint")]
     /// Constants for contain: https://drafts.csswg.org/css-contain/#contain-property
     pub struct Contain: u8 {
         /// 'size' variant, turns on size containment
         const SIZE = 0x01;
         /// `layout` variant, turns on layout containment
         const LAYOUT = 0x02;
-        /// `style` variant, turns on style containment
-        const STYLE = 0x04;
         /// `paint` variant, turns on paint containment
-        const PAINT = 0x08;
+        const PAINT = 0x04;
         /// `strict` variant, turns on all types of containment
-        const STRICT = 0x10;
-        /// 'content' variant, turns on style, layout, and paint containment
-        const CONTENT = 0x20;
+        const STRICT = 0x08;
+        /// 'content' variant, turns on layout and paint containment
+        const CONTENT = 0x10;
         /// variant with all the bits that contain: strict turns on
-        const STRICT_BITS = Contain::LAYOUT.bits | Contain::STYLE.bits | Contain::PAINT.bits | Contain::SIZE.bits;
+        const STRICT_BITS = Contain::LAYOUT.bits | Contain::PAINT.bits | Contain::SIZE.bits;
         /// variant with all the bits that contain: content turns on
-        const CONTENT_BITS = Contain::STYLE.bits | Contain::LAYOUT.bits | Contain::PAINT.bits;
+        const CONTENT_BITS = Contain::LAYOUT.bits | Contain::PAINT.bits;
     }
 }
 
@@ -803,7 +801,6 @@ impl ToCss for Contain {
         }
         maybe_write_value!(Contain::SIZE => "size");
         maybe_write_value!(Contain::LAYOUT => "layout");
-        maybe_write_value!(Contain::STYLE => "style");
         maybe_write_value!(Contain::PAINT => "paint");
 
         debug_assert!(has_any);
@@ -812,7 +809,7 @@ impl ToCss for Contain {
 }
 
 impl Parse for Contain {
-    /// none | strict | content | [ size || layout || style || paint ]
+    /// none | strict | content | [ size || layout || paint ]
     fn parse<'i, 't>(
         _context: &ParserContext,
         input: &mut Parser<'i, 't>,
@@ -822,7 +819,6 @@ impl Parse for Contain {
             let flag = match_ignore_ascii_case! { &name,
                 "size" => Some(Contain::SIZE),
                 "layout" => Some(Contain::LAYOUT),
-                "style" => Some(Contain::STYLE),
                 "paint" => Some(Contain::PAINT),
                 "strict" if result.is_empty() => return Ok(Contain::STRICT | Contain::STRICT_BITS),
                 "content" if result.is_empty() => return Ok(Contain::CONTENT | Contain::CONTENT_BITS),