feat: add create_style function with light/dark theme support

src/theme.rs

@@ -1,3 +1,5 @@
+use eframe::egui;
+use eframe::egui::Style;
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
@@ -12,6 +14,19 @@ impl Default for Theme {
     }
 }
 
+pub fn create_style(theme: &Theme) -> Style {
+    match theme {
+        Theme::Light => Style {
+            visuals: egui::Visuals::light(),
+            ..Default::default()
+        },
+        Theme::Dark => Style {
+            visuals: egui::Visuals::dark(),
+            ..Default::default()
+        },
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Settings {
     pub font_size: f32,
@@ -69,6 +84,18 @@ mod tests {
         assert_eq!(restored.theme, s.theme);
     }
 
+    #[test]
+    fn test_create_style_light_vs_dark() {
+        let light = create_style(&Theme::Light);
+        let dark = create_style(&Theme::Dark);
+        // Light and dark should have different window fills
+        assert_ne!(light.visuals.window_fill, dark.visuals.window_fill);
+        // Dark mode should have darker window
+        assert!(dark.visuals.window_fill.r() < light.visuals.window_fill.r());
+        assert!(dark.visuals.window_fill.g() < light.visuals.window_fill.g());
+        assert!(dark.visuals.window_fill.b() < light.visuals.window_fill.b());
+    }
+
     #[test]
     fn test_theme_serialize() {
         let json = serde_json::to_string(&Theme::Dark).unwrap();