diff --git a/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp b/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
index 0c0e2b67cc..1b77c3c624 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -2356,13 +2356,6 @@ void StyleComputer::invalidate_rule_cache()
     m_user_agent_rule_cache = nullptr;
 }
 
-CSSPixelRect StyleComputer::viewport_rect() const
-{
-    if (auto const navigable = document().navigable())
-        return navigable->viewport_rect();
-    return {};
-}
-
 void StyleComputer::did_load_font(FlyString const&)
 {
     document().invalidate_style();
diff --git a/Userland/Libraries/LibWeb/CSS/StyleComputer.h b/Userland/Libraries/LibWeb/CSS/StyleComputer.h
index e33a6a7e3c..d9513278a3 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleComputer.h
+++ b/Userland/Libraries/LibWeb/CSS/StyleComputer.h
@@ -109,6 +109,8 @@ public:
         Variant<Linear, CubicBezier, Steps> timing_function;
     };
 
+    void set_viewport_rect(Badge<DOM::Document>, CSSPixelRect const& viewport_rect) { m_viewport_rect = viewport_rect; }
+
 private:
     enum class ComputeStyleMode {
         Normal,
@@ -136,7 +138,8 @@ private:
     template<typename Callback>
     void for_each_stylesheet(CascadeOrigin, Callback) const;
 
-    CSSPixelRect viewport_rect() const;
+    [[nodiscard]] CSSPixelRect viewport_rect() const { return m_viewport_rect; }
+
     [[nodiscard]] Length::FontMetrics calculate_root_element_font_metrics(StyleProperties const&) const;
     CSSPixels parent_or_root_element_line_height(DOM::Element const*, Optional<CSS::Selector::PseudoElement::Type>) const;
 
@@ -241,6 +244,8 @@ private:
     mutable HashMap<AnimationKey, NonnullOwnPtr<Animation>> m_active_animations;
     mutable HashMap<AnimationKey, OwnPtr<AnimationStateSnapshot>> m_finished_animations; // If fill-mode is forward/both, this is non-null and contains the final state.
     mutable RefPtr<Platform::Timer> m_animation_driver_timer;
+
+    CSSPixelRect m_viewport_rect;
 };
 
 }
diff --git a/Userland/Libraries/LibWeb/DOM/Document.cpp b/Userland/Libraries/LibWeb/DOM/Document.cpp
index 189027e003..c8e8c72f3a 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Document.cpp
@@ -1129,6 +1129,9 @@ void Document::update_style()
     if (m_created_for_appropriate_template_contents)
         return;
 
+    // Fetch the viewport rect once, instead of repeatedly, during style computation.
+    style_computer().set_viewport_rect({}, viewport_rect());
+
     evaluate_media_rules();
 
     auto invalidation = update_style_recursively(*this);