diff --git a/AGENTS.md b/AGENTS.md
index 13aeca1..6746dfc 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -19,7 +19,7 @@ Priorities, in order:
 3. Focused, maintainable changes with good regression coverage.
 4. Performance only after correctness and testability are preserved.
 
-## Core Rules
+## Core Rucargo run --features gui --bin geolog-guiles
 
 - Use English for code, comments, docs, tests, and commit-facing text.
 - Prefer small, targeted changes over broad rewrites.
diff --git a/src/gui/panels/editor.rs b/src/gui/panels/editor.rs
index b76709b..cbf3478 100644
--- a/src/gui/panels/editor.rs
+++ b/src/gui/panels/editor.rs
@@ -53,12 +53,18 @@ impl EditorPanel {
     fn show_editor_content(&mut self, ui: &mut egui::Ui, state: &mut GuiState) {
         // Use a monospace font for code
         let font_id = egui::FontId::monospace(14.0);
+        let mut layouter = |ui: &egui::Ui, text: &dyn egui::TextBuffer, wrap_width: f32| {
+            let mut layout_job = geolog_highlighter(ui, text.as_str(), wrap_width);
+            layout_job.wrap.max_width = wrap_width;
+            ui.fonts_mut(|fonts| fonts.layout_job(layout_job))
+        };
 
         // Main editor area - simplified layout without line numbers column
         // to avoid layout instability from horizontal split calculations
         let text_edit = egui::TextEdit::multiline(&mut state.editor_content)
             .font(font_id)
             .code_editor()
+            .layouter(&mut layouter)
             .desired_width(f32::INFINITY)
             .desired_rows(20)
             .lock_focus(true);
@@ -84,24 +90,42 @@ impl Default for EditorPanel {
 }
 
 /// Simple syntax highlighting for Geolog code
-/// Returns a layouter function for egui's code_editor
-#[allow(dead_code)]
-fn geolog_highlighter(
-    _ui: &egui::Ui,
-    text: &str,
-    _wrap_width: f32,
-) -> egui::text::LayoutJob {
+fn geolog_highlighter(ui: &egui::Ui, text: &str, wrap_width: f32) -> egui::text::LayoutJob {
     let mut job = egui::text::LayoutJob::default();
+    job.wrap.max_width = wrap_width;
 
     let keywords = [
-        "theory", "instance", "query", "forall", "exists", "Sort", "Prop", "true", "false",
+        "namespace",
+        "theory",
+        "instance",
+        "query",
+        "forall",
+        "exists",
+        "chase",
+        "Sort",
+        "Prop",
+        "true",
+        "false",
     ];
 
     let font_id = egui::FontId::monospace(14.0);
-    let default_color = egui::Color32::WHITE;
-    let keyword_color = egui::Color32::from_rgb(86, 156, 214); // Blue
-    let comment_color = egui::Color32::from_rgb(106, 153, 85); // Green
-    let string_color = egui::Color32::from_rgb(206, 145, 120); // Orange
+    let default_format = egui::TextFormat::simple(font_id.clone(), ui.visuals().text_color());
+    let keyword_format = egui::TextFormat {
+        font_id: font_id.clone(),
+        color: egui::Color32::from_rgb(0, 92, 197),
+        ..Default::default()
+    };
+    let comment_format = egui::TextFormat {
+        font_id: font_id.clone(),
+        color: egui::Color32::from_rgb(35, 110, 55),
+        italics: true,
+        ..Default::default()
+    };
+    let string_format = egui::TextFormat {
+        font_id: font_id.clone(),
+        color: egui::Color32::from_rgb(145, 70, 15),
+        ..Default::default()
+    };
 
     let mut chars = text.char_indices().peekable();
 
@@ -116,11 +140,7 @@ fn geolog_highlighter(
                 }
             }
             let end = chars.peek().map(|(i, _)| *i).unwrap_or(text.len());
-            job.append(
-                &text[start..end],
-                0.0,
-                egui::TextFormat::simple(font_id.clone(), comment_color),
-            );
+            job.append(&text[start..end], 0.0, comment_format.clone());
             continue;
         }
 
@@ -136,11 +156,7 @@ fn geolog_highlighter(
                 }
             }
             let end = chars.peek().map(|(i, _)| *i).unwrap_or(text.len());
-            job.append(
-                &text[start..end],
-                0.0,
-                egui::TextFormat::simple(font_id.clone(), string_color),
-            );
+            job.append(&text[start..end], 0.0, string_format.clone());
             continue;
         }
 
@@ -153,27 +169,54 @@ fn geolog_highlighter(
             let end = chars.peek().map(|(i, _)| *i).unwrap_or(text.len());
             let word = &text[start..end];
 
-            let color = if keywords.contains(&word) {
-                keyword_color
+            let format = if keywords.contains(&word) {
+                keyword_format.clone()
             } else {
-                default_color
+                default_format.clone()
             };
 
-            job.append(
-                word,
-                0.0,
-                egui::TextFormat::simple(font_id.clone(), color),
-            );
+            job.append(word, 0.0, format);
             continue;
         }
 
         // Default: single character
-        job.append(
-            &text[i..i + c.len_utf8()],
-            0.0,
-            egui::TextFormat::simple(font_id.clone(), default_color),
-        );
+        job.append(&text[i..i + c.len_utf8()], 0.0, default_format.clone());
     }
 
     job
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn highlighter_marks_keywords_comments_and_strings() {
+        egui::__run_test_ui(|ui| {
+            let job = geolog_highlighter(
+                ui,
+                "theory Demo { // note\n  label = \"hi\";\n}",
+                f32::INFINITY,
+            );
+
+            assert!(!job.sections.is_empty());
+
+            let has_keyword = job
+                .sections
+                .iter()
+                .any(|section| section.format.color == egui::Color32::from_rgb(0, 92, 197));
+            let has_comment = job
+                .sections
+                .iter()
+                .any(|section| section.format.color == egui::Color32::from_rgb(35, 110, 55));
+            let has_string = job
+                .sections
+                .iter()
+                .any(|section| section.format.color == egui::Color32::from_rgb(145, 70, 15));
+
+            assert!(has_keyword);
+            assert!(has_comment);
+            assert!(has_string);
+        });
+    }
+}