diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp
index c5fb5df6c3a..a6e9b61aeb6 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp
@@ -14,12 +14,12 @@ namespace Web::CSS {
 
 JS_DEFINE_ALLOCATOR(CSSStyleRule);
 
-JS::NonnullGCPtr<CSSStyleRule> CSSStyleRule::create(JS::Realm& realm, Vector<NonnullRefPtr<Web::CSS::Selector>>&& selectors, CSSStyleDeclaration& declaration)
+JS::NonnullGCPtr<CSSStyleRule> CSSStyleRule::create(JS::Realm& realm, Vector<NonnullRefPtr<Web::CSS::Selector>>&& selectors, PropertyOwningCSSStyleDeclaration& declaration)
 {
     return realm.heap().allocate<CSSStyleRule>(realm, realm, move(selectors), declaration);
 }
 
-CSSStyleRule::CSSStyleRule(JS::Realm& realm, Vector<NonnullRefPtr<Selector>>&& selectors, CSSStyleDeclaration& declaration)
+CSSStyleRule::CSSStyleRule(JS::Realm& realm, Vector<NonnullRefPtr<Selector>>&& selectors, PropertyOwningCSSStyleDeclaration& declaration)
     : CSSRule(realm)
     , m_selectors(move(selectors))
     , m_declaration(declaration)
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h
index dd604454cec..ab46be00a52 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleRule.h
@@ -19,12 +19,12 @@ class CSSStyleRule final : public CSSRule {
     JS_DECLARE_ALLOCATOR(CSSStyleRule);
 
 public:
-    [[nodiscard]] static JS::NonnullGCPtr<CSSStyleRule> create(JS::Realm&, Vector<NonnullRefPtr<Selector>>&&, CSSStyleDeclaration&);
+    [[nodiscard]] static JS::NonnullGCPtr<CSSStyleRule> create(JS::Realm&, Vector<NonnullRefPtr<Selector>>&&, PropertyOwningCSSStyleDeclaration&);
 
     virtual ~CSSStyleRule() override = default;
 
     Vector<NonnullRefPtr<Selector>> const& selectors() const { return m_selectors; }
-    CSSStyleDeclaration const& declaration() const { return m_declaration; }
+    PropertyOwningCSSStyleDeclaration const& declaration() const { return m_declaration; }
 
     virtual Type type() const override { return Type::Style; }
 
@@ -34,14 +34,14 @@ public:
     CSSStyleDeclaration* style();
 
 private:
-    CSSStyleRule(JS::Realm&, Vector<NonnullRefPtr<Selector>>&&, CSSStyleDeclaration&);
+    CSSStyleRule(JS::Realm&, Vector<NonnullRefPtr<Selector>>&&, PropertyOwningCSSStyleDeclaration&);
 
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
     virtual String serialized() const override;
 
     Vector<NonnullRefPtr<Selector>> m_selectors;
-    JS::NonnullGCPtr<CSSStyleDeclaration> m_declaration;
+    JS::NonnullGCPtr<PropertyOwningCSSStyleDeclaration> m_declaration;
 };
 
 template<>
diff --git a/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp b/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
index 2fcb67ee11d..0fab61e542c 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -730,7 +730,7 @@ void StyleComputer::cascade_declarations(StyleProperties& style, DOM::Element& e
     auto properties_for_revert = style.properties();
 
     for (auto const& match : matching_rules) {
-        for (auto const& property : verify_cast<PropertyOwningCSSStyleDeclaration>(match.rule->declaration()).properties()) {
+        for (auto const& property : match.rule->declaration().properties()) {
             if (important != property.important)
                 continue;
 
@@ -772,7 +772,7 @@ static void cascade_custom_properties(DOM::Element& element, Optional<CSS::Selec
 {
     size_t needed_capacity = 0;
     for (auto const& matching_rule : matching_rules)
-        needed_capacity += verify_cast<PropertyOwningCSSStyleDeclaration>(matching_rule.rule->declaration()).custom_properties().size();
+        needed_capacity += matching_rule.rule->declaration().custom_properties().size();
 
     if (!pseudo_element.has_value()) {
         if (auto const inline_style = element.inline_style())
@@ -783,7 +783,7 @@ static void cascade_custom_properties(DOM::Element& element, Optional<CSS::Selec
     custom_properties.ensure_capacity(needed_capacity);
 
     for (auto const& matching_rule : matching_rules) {
-        for (auto const& it : verify_cast<PropertyOwningCSSStyleDeclaration>(matching_rule.rule->declaration()).custom_properties())
+        for (auto const& it : matching_rule.rule->declaration().custom_properties())
             custom_properties.set(it.key, it.value);
     }
 
diff --git a/Userland/Libraries/LibWeb/Dump.cpp b/Userland/Libraries/LibWeb/Dump.cpp
index bfa0ec5834d..8378b9ea77b 100644
--- a/Userland/Libraries/LibWeb/Dump.cpp
+++ b/Userland/Libraries/LibWeb/Dump.cpp
@@ -694,15 +694,14 @@ ErrorOr<void> dump_style_rule(StringBuilder& builder, CSS::CSSStyleRule const& r
     }
     indent(builder, indent_levels);
     builder.append("  Declarations:\n"sv);
-    auto& style_declaration = verify_cast<CSS::PropertyOwningCSSStyleDeclaration>(rule.declaration());
-    for (auto& property : style_declaration.properties()) {
+    for (auto& property : rule.declaration().properties()) {
         indent(builder, indent_levels);
         builder.appendff("    {}: '{}'", CSS::string_from_property_id(property.property_id), property.value->to_string());
         if (property.important == CSS::Important::Yes)
             builder.append(" \033[31;1m!important\033[0m"sv);
         builder.append('\n');
     }
-    for (auto& property : style_declaration.custom_properties()) {
+    for (auto& property : rule.declaration().custom_properties()) {
         indent(builder, indent_levels);
         builder.appendff("    {}: '{}'", property.key, property.value.value->to_string());
         if (property.value.important == CSS::Important::Yes)