diff --git a/src/interpreter/mod.rs b/src/interpreter/mod.rs
index 1232186..05e75c9 100644
--- a/src/interpreter/mod.rs
+++ b/src/interpreter/mod.rs
@@ -529,7 +529,7 @@ impl Interpreter {
             .map(|(k, v)| (k.to_string(), v.to_string()))
             .collect();
 
-        stylesheet.matching_rules(el.type_name, el_id, &classes, active_pseudo, structural, ancestors, preceding_siblings, &el_attributes)
+        stylesheet.matching_rules(Some(el.element_id), el.type_name, el_id, &classes, active_pseudo, structural, ancestors, preceding_siblings, &el_attributes)
     }
 
     fn resolve_prop(v: &str, variables: &HashMap<String, Value>, rhei: &RheiContext) -> String {
diff --git a/src/interpreter/style.rs b/src/interpreter/style.rs
index 9ce1369..111b84b 100644
--- a/src/interpreter/style.rs
+++ b/src/interpreter/style.rs
@@ -1,5 +1,7 @@
 use std::collections::HashMap;
 use std::borrow::Cow;
+use std::cell::RefCell;
+use super::reactive::ElementId;
 
 
 #[derive(Debug, Clone)]
@@ -490,6 +492,7 @@ impl StyleSheet {
 
     pub fn matching_rules<'a>(
         &'a self,
+        element_id: Option<ElementId>,
         type_name: &str,
         el_id: Option<&str>,
         el_classes: &[&str],
@@ -499,8 +502,9 @@ impl StyleSheet {
         preceding_siblings: &[AncestorInfo],
         el_attributes: &HashMap<String, String>,
     ) -> Vec<&'a HashMap<String, String>> {
-        self.index.query(
-            type_name, el_id, el_classes, active_pseudo,
+        self.index.query_cached(
+            element_id, active_pseudo,
+            type_name, el_id, el_classes,
             structural, ancestors, preceding_siblings, el_attributes,
         )
     }
@@ -508,6 +512,7 @@ impl StyleSheet {
     pub fn matching_pseudo_rules(
         &self,
         pseudo: &str,
+        element_id: Option<ElementId>,
         type_name: &str,
         el_id: Option<&str>,
         el_classes: &[&str],
@@ -518,7 +523,7 @@ impl StyleSheet {
     ) -> HashMap<String, String> {
         let mut props = HashMap::new();
         let all_sheets = self.matching_rules(
-            type_name, el_id, el_classes, &[pseudo],
+            element_id, type_name, el_id, el_classes, &[pseudo],
             structural, ancestors, preceding_siblings, el_attributes,
         );
         for sheet in &all_sheets {
@@ -555,6 +560,10 @@ pub struct StyleIndex {
     rules: Vec<StyleRule>,
     /// Epoch counter: incremented on rebuild, used for cache invalidation
     epoch: u64,
+    /// Cache: element_id → (matched_rule_ids, epoch_at_insert)
+    match_cache: RefCell<HashMap<ElementId, (Vec<RuleId>, u64)>>,
+    /// Cache for pseudo-class matches: (element_id, pseudo_class) → (matched_rule_ids, epoch)
+    pseudo_cache: RefCell<HashMap<(ElementId, String), (Vec<RuleId>, u64)>>,
 }
 
 impl StyleIndex {
@@ -568,6 +577,8 @@ impl StyleIndex {
             complex_rules: Vec::new(),
             rules: Vec::new(),
             epoch: 0,
+            match_cache: RefCell::new(HashMap::new()),
+            pseudo_cache: RefCell::new(HashMap::new()),
         };
 
         // Sort rules by specificity once
@@ -624,6 +635,72 @@ impl StyleIndex {
         self.epoch
     }
 
+    pub fn query_cached<'a>(
+        &'a self,
+        element_id: Option<ElementId>,
+        active_pseudo: &[&str],
+        type_name: &str,
+        el_id: Option<&str>,
+        el_classes: &[&str],
+        structural: &StructuralContext,
+        ancestors: &[AncestorInfo],
+        preceding_siblings: &[AncestorInfo],
+        el_attributes: &HashMap<String, String>,
+    ) -> Vec<&'a HashMap<String, String>> {
+        let eid = match element_id {
+            Some(id) => id,
+            None => return self.query(
+                type_name, el_id, el_classes, active_pseudo,
+                structural, ancestors, preceding_siblings, el_attributes,
+            ),
+        };
+
+        // Check cache
+        if active_pseudo.is_empty() {
+            let cache = self.match_cache.borrow();
+            if let Some((cached_ids, cached_epoch)) = cache.get(&eid) {
+                if *cached_epoch == self.epoch {
+                    return cached_ids.iter().map(|&rid| &self.rules[rid].properties).collect();
+                }
+            }
+        } else {
+            let pseudo_key = active_pseudo.join(",");
+            let cache = self.pseudo_cache.borrow();
+            if let Some((cached_ids, cached_epoch)) = cache.get(&(eid, pseudo_key)) {
+                if *cached_epoch == self.epoch {
+                    return cached_ids.iter().map(|&rid| &self.rules[rid].properties).collect();
+                }
+            }
+        }
+
+        // Cache miss — run full query
+        let result = self.query(
+            type_name, el_id, el_classes, active_pseudo,
+            structural, ancestors, preceding_siblings, el_attributes,
+        );
+
+        // Extract rule IDs from matched results (track which rules matched)
+        let matched_ids: Vec<RuleId> = {
+            result.iter().filter_map(|props| {
+                self.rules.iter().position(|r| &r.properties == *props)
+            }).collect()
+        };
+
+        // Populate cache (short-lived mutable borrow)
+        if active_pseudo.is_empty() {
+            if !matched_ids.is_empty() || self.match_cache.borrow().len() < 2048 {
+                self.match_cache.borrow_mut().insert(eid, (matched_ids, self.epoch));
+            }
+        } else {
+            let pseudo_key = active_pseudo.join(",");
+            if !matched_ids.is_empty() || self.pseudo_cache.borrow().len() < 1024 {
+                self.pseudo_cache.borrow_mut().insert((eid, pseudo_key), (matched_ids, self.epoch));
+            }
+        }
+
+        result
+    }
+
     pub fn query<'a>(
         &'a self,
         type_name: &str,
@@ -705,9 +782,25 @@ impl StyleIndex {
         let mut seen = std::collections::HashSet::new();
         candidates.retain(|r| seen.insert(*r));
 
-        // Test candidates against full selector
+        // Merge candidate and complex matches in a single pass.
+        // Both lists reference self.rules, which is already sorted by specificity,
+        // so we collect all matches and they stay in insertion order.
         let mut matched: Vec<&StyleRule> = Vec::new();
+        let mut ci = 0usize;
+
         for &rid in &candidates {
+            // Insert any complex rules that precede this candidate in the sorted rules
+            while ci < self.complex_rules.len() && self.complex_rules[ci].1 < rid {
+                let (sel, crid) = &self.complex_rules[ci];
+                if sel.matches(
+                    type_name, el_id, el_classes, active_pseudo,
+                    structural, ancestors, preceding_siblings, el_attributes,
+                ) {
+                    matched.push(&self.rules[*crid]);
+                }
+                ci += 1;
+            }
+
             let rule = &self.rules[rid];
             if rule.selector.matches(
                 type_name, el_id, el_classes, active_pseudo,
@@ -717,24 +810,16 @@ impl StyleIndex {
             }
         }
 
-        // Test complex rules
-        for (sel, rid) in &self.complex_rules {
+        // Remaining complex rules
+        for (sel, crid) in &self.complex_rules[ci..] {
             if sel.matches(
                 type_name, el_id, el_classes, active_pseudo,
                 structural, ancestors, preceding_siblings, el_attributes,
             ) {
-                matched.push(&self.rules[*rid]);
+                matched.push(&self.rules[*crid]);
             }
         }
 
-        // Re-sort matched by specificity (candidates are already sorted)
-        // but we only need to sort the matched subset
-        matched.sort_by(|a, b| {
-            a.selector
-                .specificity()
-                .cmp(&b.selector.specificity())
-        });
-
         matched.into_iter().map(|r| &r.properties).collect()
     }
 }
diff --git a/src/renderer.rs b/src/renderer.rs
index 0ef27be..9d5defb 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -59,10 +59,10 @@ pub fn collect_hover_active<'a>(
         .collect();
 
     let hover_props = stylesheet.matching_pseudo_rules(
-        "hover", el.type_name, el_id, &classes, &default_struct, &[], &[], &el_attributes,
+        "hover", Some(el.element_id), el.type_name, el_id, &classes, &default_struct, &[], &[], &el_attributes,
     );
     let active_props = stylesheet.matching_pseudo_rules(
-        "active", el.type_name, el_id, &classes, &default_struct, &[], &[], &el_attributes,
+        "active", Some(el.element_id), el.type_name, el_id, &classes, &default_struct, &[], &[], &el_attributes,
     );
 
     (hover_props, active_props)
@@ -1032,9 +1032,9 @@ fn render_button<'a>(
         .map(|(k, v)| (k.to_string(), v.to_string()))
         .collect();
     let hover_sheets: Vec<&HashMap<String, String>> =
-        stylesheet.matching_rules(el.type_name, el_id, &classes, &["hover"], &default_struct, &[], &[], &el_attributes);
+        stylesheet.matching_rules(Some(el.element_id), el.type_name, el_id, &classes, &["hover"], &default_struct, &[], &[], &el_attributes);
     let active_sheets: Vec<&HashMap<String, String>> =
-        stylesheet.matching_rules(el.type_name, el_id, &classes, &["active"], &default_struct, &[], &[], &el_attributes);
+        stylesheet.matching_rules(Some(el.element_id), el.type_name, el_id, &classes, &["active"], &default_struct, &[], &[], &el_attributes);
 
     let mut hover_props = std::collections::HashMap::new();
     for sheet in &hover_sheets {