diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_cpp.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_cpp.cpp
index d82e9efdfc..5b9a817098 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_cpp.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_cpp.cpp
@@ -127,6 +127,34 @@ bool is_inherited_property(PropertyID property_id)
     }
 }
 
+bool property_affects_layout(PropertyID property_id)
+{
+    switch (property_id) {
+)~~~");
+
+    properties.for_each_member([&](auto& name, auto& value) {
+        VERIFY(value.is_object());
+
+        bool affects_layout = true;
+        if (value.as_object().has("affects-layout"))
+            affects_layout = value.as_object().get("affects-layout").to_bool();
+
+        if (affects_layout) {
+            auto member_generator = generator.fork();
+            member_generator.set("name:titlecase", title_casify(name));
+            member_generator.append(R"~~~(
+    case PropertyID::@name:titlecase@:
+)~~~");
+        }
+    });
+
+    generator.append(R"~~~(
+        return true;
+    default:
+        return false;
+    }
+}
+
 NonnullRefPtr<StyleValue> property_initial_value(PropertyID property_id)
 {
     static Array<RefPtr<StyleValue>, to_underlying(last_property_id) + 1> initial_values;
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_h.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_h.cpp
index d6db7a7008..c3a86fc5d1 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_h.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/Generate_CSS_PropertyID_h.cpp
@@ -89,6 +89,8 @@ NonnullRefPtr<StyleValue> property_initial_value(PropertyID);
 bool property_accepts_value(PropertyID, StyleValue&);
 size_t property_maximum_value_count(PropertyID);
 
+bool property_affects_layout(PropertyID);
+
 constexpr PropertyID first_property_id = PropertyID::@first_property_id@;
 constexpr PropertyID last_property_id = PropertyID::@last_property_id@;
 constexpr PropertyID first_shorthand_property_id = PropertyID::@first_shorthand_property_id@;
diff --git a/Userland/Libraries/LibWeb/CSS/Properties.json b/Userland/Libraries/LibWeb/CSS/Properties.json
index 7188ed48c3..cc67da4006 100644
--- a/Userland/Libraries/LibWeb/CSS/Properties.json
+++ b/Userland/Libraries/LibWeb/CSS/Properties.json
@@ -43,6 +43,7 @@
     ]
   },
   "background-color": {
+    "affects-layout": false,
     "inherited": false,
     "initial": "transparent",
     "valid-types": [
@@ -501,6 +502,7 @@
     ]
   },
   "color": {
+    "affects-layout": false,
     "inherited": true,
     "initial": "-libweb-palette-base-text",
     "valid-types": [
@@ -1049,6 +1051,7 @@
     ]
   },
   "outline-width": {
+    "affects-layout": false,
     "inherited": false,
     "initial": "medium",
     "valid-types": [
@@ -1243,6 +1246,7 @@
   },
   "text-decoration-line": {
     "__comment": "FIXME: This property is not supposed to be inherited, but we currently rely on inheritance to propagate decorations into line boxes.",
+    "affects-layout": false,
     "inherited": true,
     "initial": "none",
     "valid-identifiers": [