src/main/java/sbu/javafx/MusicApp.java

@@ -3,6 +3,7 @@ package sbu.javafx;
 import javafx.application.Application;
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Scene;
+import javafx.scene.image.Image;
 import javafx.stage.Stage;
 
 public class MusicApp extends Application {
@@ -13,6 +14,7 @@ public class MusicApp extends Application {
                 getClass().getResource("App-view.fxml"));
         Scene scene = new Scene(loader.load());
         stage.setTitle("Music Player");
+        stage.getIcons().add(new Image("/sbu/images/default-cover.png"));
         stage.setScene(scene);
         stage.setResizable(false);
         stage.show();

src/main/java/sbu/javafx/MusicController.java

@@ -60,6 +60,10 @@ public class MusicController {
     private boolean isShuffle = false;
     private boolean isRepeat = false;
 
+    // theme button
+    @FXML private Button themeBtn;
+    private boolean isDarkMode = false;
+
     //  ========================================= Methods ============================================
     public void initialize(){ // runs without calling
         libraryView.setItems(library);
@@ -461,4 +465,18 @@ public class MusicController {
         libraryTabBtn.getStyleClass().remove("tab-active");
     }
 
+    // theme controller
+    @FXML
+    public void handleThemeToggle() {
+        isDarkMode = !isDarkMode;
+        javafx.scene.Scene scene = themeBtn.getScene();
+
+        if (isDarkMode) {
+            scene.getRoot().getStyleClass().add("dark");
+            themeBtn.setText("☀️");
+        } else {
+            scene.getRoot().getStyleClass().remove("dark");
+            themeBtn.setText("🌙");
+        }
+    }
 }

src/main/resources/sbu/javafx/App-view.fxml

@@ -24,6 +24,12 @@
          spacing="20"
          prefWidth="320">
 
+      <!-- Dark Mode Toggle -->
+      <HBox alignment="TOP_RIGHT" fillHeight="false">
+         <Button fx:id="themeBtn" text="🌙" styleClass="theme-btn"
+                 onAction="#handleThemeToggle"/>
+      </HBox>
+
       <padding>
          <Insets top="32" right="28" bottom="32" left="28"/>
       </padding>

src/main/resources/sbu/javafx/style.css

@@ -124,13 +124,6 @@
     -fx-background-color: #FAFAFA;
 }
 
-.playlist-header {
-    -fx-font-size: 14px;
-    -fx-font-weight: bold;
-    -fx-text-fill: #424242;
-    -fx-padding: 0 0 8 0;
-}
-
 /* ===== ListView ===== */
 .playlist {
     -fx-background-color: transparent;
@@ -247,7 +240,144 @@
     -fx-text-fill: #212121;
 }
 
-/* ===== Album Cover rounded corners ===== */
+/* ===== Theme Button ===== */
-.cover-container {
+.theme-btn {
-    -fx-background-radius: 12px;
+    -fx-background-color: transparent;
+    -fx-font-size: 16px;
+    -fx-cursor: hand;
+    -fx-padding: 4 8 4 8;
+    -fx-background-radius: 6px;
+}
+
+.theme-btn:hover {
+    -fx-background-color: #F0F0F0;
+}
+
+/* ========================================= */
+/* ===== Dark Mode ===== */
+/* ========================================= */
+
+.dark .root {
+    -fx-background-color: #121212;
+}
+
+.dark .player-panel {
+    -fx-background-color: #1E1E1E;
+    -fx-border-color: #333333;
+}
+
+.dark .playlist-panel {
+    -fx-background-color: #121212;
+}
+
+.dark .cover-container {
+    -fx-background-color: #2A2A2A;
+}
+
+.dark .song-title {
+    -fx-text-fill: #FFFFFF;
+}
+
+.dark .artist-name {
+    -fx-text-fill: #AAAAAA;
+}
+
+.dark .time-label {
+    -fx-text-fill: #666666;
+}
+
+.dark .progress-slider .track {
+    -fx-background-color: #333333;
+}
+
+.dark .progress-slider .thumb {
+    -fx-background-color: #FFFFFF;
+}
+
+.dark .volume-slider .track {
+    -fx-background-color: #333333;
+}
+
+.dark .volume-slider .thumb {
+    -fx-background-color: #FFFFFF;
+}
+
+.dark .play-btn {
+    -fx-background-color: #FFFFFF;
+    -fx-text-fill: #000000;
+}
+
+.dark .play-btn:hover {
+    -fx-background-color: #DDDDDD;
+}
+
+.dark .control-btn {
+    -fx-text-fill: #FFFFFF;
+}
+
+.dark .control-btn:hover {
+    -fx-background-color: #2A2A2A;
+}
+
+.dark .theme-btn:hover {
+    -fx-background-color: #2A2A2A;
+}
+
+.dark .tab-bar {
+    -fx-background-color: #1A1A1A;
+    -fx-border-color: #333333;
+}
+
+.dark .tab-btn {
+    -fx-text-fill: #9E9E9E;
+}
+
+.dark .tab-active {
+    -fx-text-fill: #FFFFFF;
+    -fx-border-color: transparent transparent #FFFFFF transparent;
+}
+
+.dark .tab-content {
+    -fx-background-color: #121212;
+}
+
+.dark .tab-header {
+    -fx-text-fill: #FFFFFF;
+}
+
+.dark .playlist .list-cell {
+    -fx-background-color: transparent;
+    -fx-text-fill: #CCCCCC;
+    -fx-border-color: transparent transparent #222222 transparent;
+}
+
+.dark .playlist .list-cell:hover {
+    -fx-background-color: #1E1E1E;
+}
+
+.dark .playlist .list-cell:selected {
+    -fx-background-color: #2A2A2A;
+    -fx-text-fill: #FFFFFF;
+}
+
+.dark .playlist .scroll-bar:vertical .thumb {
+    -fx-background-color: #444444;
+}
+
+.dark .add-btn {
+    -fx-background-color: #FFFFFF;
+    -fx-text-fill: #000000;
+}
+
+.dark .add-btn:hover {
+    -fx-background-color: #DDDDDD;
+}
+
+.dark .back-btn {
+    -fx-text-fill: #9E9E9E;
+}
+
+.dark .back-btn:hover {
+    -fx-background-color: #2A2A2A;
+    -fx-text-fill: #FFFFFF;
 }