4 files changed, 24 insertions, 10 deletions
diff --git a/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp b/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
index 2e4931b45a..0f4c201f8c 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -141,7 +141,7 @@ void StyleComputer::for_each_stylesheet(CascadeOrigin cascade_origin, Callback c
     }
     if (cascade_origin == CascadeOrigin::Author) {
         for (auto const& sheet : document().style_sheets().sheets()) {
-            callback(sheet);
+            callback(*sheet);
         }
     }
 }
diff --git a/Userland/Libraries/LibWeb/CSS/StyleSheetList.cpp b/Userland/Libraries/LibWeb/CSS/StyleSheetList.cpp
index 02639fe93c..d2c0b8d759 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleSheetList.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleSheetList.cpp
@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/QuickSort.h>
 #include <LibWeb/Bindings/StyleSheetListPrototype.h>
 #include <LibWeb/CSS/StyleSheetList.h>
 #include <LibWeb/DOM/Document.h>
@@ -15,6 +16,8 @@ void StyleSheetList::add_sheet(CSSStyleSheet& sheet)
     sheet.set_style_sheet_list({}, this);
     m_sheets.append(sheet);
 
+    sort_sheets();
+
     m_document.style_computer().invalidate_rule_cache();
     m_document.style_computer().load_fonts_from_sheet(sheet);
     m_document.invalidate_style();
@@ -23,7 +26,9 @@ void StyleSheetList::add_sheet(CSSStyleSheet& sheet)
 void StyleSheetList::remove_sheet(CSSStyleSheet& sheet)
 {
     sheet.set_style_sheet_list({}, nullptr);
-    m_sheets.remove_first_matching([&](auto& entry) { return &entry == &sheet; });
+    m_sheets.remove_first_matching([&](auto& entry) { return entry.ptr() == &sheet; });
+
+    sort_sheets();
 
     m_document.style_computer().invalidate_rule_cache();
     m_document.invalidate_style();
@@ -45,8 +50,8 @@ void StyleSheetList::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visitor.visit(m_document);
-    for (auto& sheet : m_sheets)
-        visitor.visit(&sheet);
+    for (auto sheet : m_sheets)
+        visitor.visit(sheet.ptr());
 }
 
 // https://www.w3.org/TR/cssom/#ref-for-dfn-supported-property-indices%E2%91%A1
@@ -65,7 +70,14 @@ JS::Value StyleSheetList::item_value(size_t index) const
     if (index >= m_sheets.size())
         return JS::js_undefined();
 
-    return &m_sheets[index];
+    return m_sheets[index].ptr();
+}
+
+void StyleSheetList::sort_sheets()
+{
+    quick_sort(m_sheets, [](JS::NonnullGCPtr<StyleSheet> a, JS::NonnullGCPtr<StyleSheet> b) {
+        return a->owner_node()->is_before(*b->owner_node());
+    });
 }
 
 }
diff --git a/Userland/Libraries/LibWeb/CSS/StyleSheetList.h b/Userland/Libraries/LibWeb/CSS/StyleSheetList.h
index 35bd63896a..96f8908a21 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleSheetList.h
+++ b/Userland/Libraries/LibWeb/CSS/StyleSheetList.h
@@ -20,14 +20,14 @@ public:
     void add_sheet(CSSStyleSheet&);
     void remove_sheet(CSSStyleSheet&);
 
-    Vector<CSSStyleSheet&> const& sheets() const { return m_sheets; }
-    Vector<CSSStyleSheet&>& sheets() { return m_sheets; }
+    Vector<JS::NonnullGCPtr<CSSStyleSheet>> const& sheets() const { return m_sheets; }
+    Vector<JS::NonnullGCPtr<CSSStyleSheet>>& sheets() { return m_sheets; }
 
     CSSStyleSheet* item(size_t index) const
     {
         if (index >= m_sheets.size())
             return {};
-        return &const_cast<CSSStyleSheet&>(m_sheets[index]);
+        return const_cast<CSSStyleSheet*>(m_sheets[index].ptr());
     }
 
     size_t length() const { return m_sheets.size(); }
@@ -43,8 +43,10 @@ private:
 
     virtual void visit_edges(Cell::Visitor&) override;
 
+    void sort_sheets();
+
     DOM::Document& m_document;
-    Vector<CSSStyleSheet&> m_sheets;
+    Vector<JS::NonnullGCPtr<CSSStyleSheet>> m_sheets;
 };
 
 }
diff --git a/Userland/Libraries/LibWeb/DOM/Document.cpp b/Userland/Libraries/LibWeb/DOM/Document.cpp
index 5de2904b39..9efe823ab4 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Document.cpp
@@ -1582,7 +1582,7 @@ void Document::evaluate_media_rules()
 {
     bool any_media_queries_changed_match_state = false;
     for (auto& style_sheet : style_sheets().sheets()) {
-        if (style_sheet.evaluate_media_queries(window()))
+        if (style_sheet->evaluate_media_queries(window()))
             any_media_queries_changed_match_state = true;
     }