diff --git a/src/ui/mod.rs b/src/ui/mod.rs
index f77092d..ba51e35 100644
--- a/src/ui/mod.rs
+++ b/src/ui/mod.rs
@@ -12,6 +12,8 @@ mod setup_test;
 #[cfg(test)]
 mod curriculum_test;
 pub mod systems;
+#[cfg(test)]
+mod systems_test;
 pub mod target;
 
 use bevy::prelude::*;
diff --git a/src/ui/systems_test.rs b/src/ui/systems_test.rs
new file mode 100644
index 0000000..9946fc0
--- /dev/null
+++ b/src/ui/systems_test.rs
@@ -0,0 +1,107 @@
+//! Tests for the UI interaction systems.
+
+#[cfg(test)]
+mod tests {
+    use bevy::prelude::*;
+    use crate::ui::systems::mode_toggle_system;
+    use crate::resources::{SequenceState, SequenceMode};
+    use crate::components::SequenceModeButton;
+
+    #[test]
+    fn test_mode_toggle_system_random_to_ordered() {
+        let mut app = App::new();
+
+        let mut seq_state = SequenceState::default();
+        seq_state.mode = SequenceMode::Random;
+        seq_state.current_ordered_value = 5;
+        app.insert_resource(seq_state);
+
+        app.add_systems(Update, mode_toggle_system);
+
+        let entity = app.world_mut().spawn((
+            SequenceModeButton,
+            Interaction::Pressed,
+            BackgroundColor(Color::NONE),
+        )).id();
+        let text_entity = app.world_mut().spawn(Text::new("Mode: Random")).id();
+        app.world_mut().entity_mut(entity).add_child(text_entity);
+
+        app.update();
+
+        let state = app.world().resource::<SequenceState>();
+        assert_eq!(state.mode, SequenceMode::Ordered, "Mode should change to Ordered.");
+        assert_eq!(state.current_ordered_value, 0, "Ordered value should reset to 0.");
+
+        let text = app.world().get::<Text>(text_entity).unwrap();
+        assert_eq!(text.0, "Mode: Ordered", "Text should update to Mode: Ordered.");
+    }
+
+    #[test]
+    fn test_mode_toggle_system_ordered_to_random() {
+        let mut app = App::new();
+
+        let mut seq_state = SequenceState::default();
+        seq_state.mode = SequenceMode::Ordered;
+        seq_state.current_ordered_value = 5;
+        app.insert_resource(seq_state);
+
+        app.add_systems(Update, mode_toggle_system);
+
+        let entity = app.world_mut().spawn((
+            SequenceModeButton,
+            Interaction::Pressed,
+            BackgroundColor(Color::NONE),
+        )).id();
+        let text_entity = app.world_mut().spawn(Text::new("Mode: Ordered")).id();
+        app.world_mut().entity_mut(entity).add_child(text_entity);
+
+        app.update();
+
+        let state = app.world().resource::<SequenceState>();
+        assert_eq!(state.mode, SequenceMode::Random, "Mode should change to Random.");
+        assert_eq!(state.current_ordered_value, 0, "Ordered value should reset to 0.");
+
+        let text = app.world().get::<Text>(text_entity).unwrap();
+        assert_eq!(text.0, "Mode: Random", "Text should update to Mode: Random.");
+    }
+
+    #[test]
+    fn test_mode_toggle_system_hovered() {
+        let mut app = App::new();
+        app.insert_resource(SequenceState::default());
+        app.add_systems(Update, mode_toggle_system);
+
+        let entity = app.world_mut().spawn((
+            SequenceModeButton,
+            Interaction::Hovered,
+            BackgroundColor(Color::NONE),
+        )).id();
+        let text_entity = app.world_mut().spawn(Text::new("Mode: Random")).id();
+        app.world_mut().entity_mut(entity).add_child(text_entity);
+
+        app.update();
+
+        let bg_color = app.world().get::<BackgroundColor>(entity).unwrap();
+        assert_eq!(bg_color.0, Color::srgba(0.886, 0.886, 0.886, 0.1), "Background color should be subtle gray on hover.");
+    }
+
+    #[test]
+    fn test_mode_toggle_system_none() {
+        let mut app = App::new();
+        app.insert_resource(SequenceState::default());
+        app.add_systems(Update, mode_toggle_system);
+
+        let entity = app.world_mut().spawn((
+            SequenceModeButton,
+            Interaction::None,
+            BackgroundColor(Color::srgba(1.0, 0.0, 0.0, 1.0)),
+        )).id();
+        let text_entity = app.world_mut().spawn(Text::new("Mode: Random")).id();
+        app.world_mut().entity_mut(entity).add_child(text_entity);
+
+        app.update();
+
+        let bg_color = app.world().get::<BackgroundColor>(entity).unwrap();
+        assert_eq!(bg_color.0, Color::NONE, "Background color should reset to NONE.");
+    }
+}