diff --git a/app/src/processing/app/Base.java b/app/src/processing/app/Base.java
index 9638557bc..7af391540 100644
--- a/app/src/processing/app/Base.java
+++ b/app/src/processing/app/Base.java
@@ -35,6 +35,9 @@ import java.util.Map.Entry;
 import javax.swing.*;
 import javax.swing.tree.DefaultMutableTreeNode;
 
+import com.formdev.flatlaf.FlatDarkLaf;
+import com.formdev.flatlaf.FlatLaf;
+import com.formdev.flatlaf.FlatLightLaf;
 import processing.app.contrib.*;
 import processing.app.tools.Tool;
 import processing.app.ui.*;
@@ -270,6 +273,7 @@ public class Base {
       Messages.log("About to create Base..."); //$NON-NLS-1$
       try {
         final Base base = new Base(args);
+        base.updateTheme();
         Messages.log("Base() constructor succeeded");
 //        t6 = System.currentTimeMillis();
 
@@ -299,6 +303,18 @@ public class Base {
 
 
   public void updateTheme() {
+    try {
+      FlatLaf laf = "dark".equals(Theme.get("laf.mode")) ?
+        new FlatDarkLaf() : new FlatLightLaf();
+      laf.setExtraDefaults(Collections.singletonMap("@accentColor",
+        Theme.get("laf.accent.color")));
+      //UIManager.setLookAndFeel(laf);
+      FlatLaf.setup(laf);
+
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+
     ContributionManager.updateTheme();
     for (Editor editor : getEditors()) {
       editor.updateTheme();
diff --git a/app/src/processing/app/platform/DefaultPlatform.java b/app/src/processing/app/platform/DefaultPlatform.java
index a171c13ad..58fe76063 100644
--- a/app/src/processing/app/platform/DefaultPlatform.java
+++ b/app/src/processing/app/platform/DefaultPlatform.java
@@ -32,11 +32,15 @@ import javax.swing.UIManager;
 import javax.swing.plaf.FontUIResource;
 import javax.swing.text.StyleContext;
 
+import com.formdev.flatlaf.FlatDarkLaf;
+import com.formdev.flatlaf.FlatLaf;
+import com.formdev.flatlaf.FlatLightLaf;
 import com.sun.jna.Library;
 import com.sun.jna.Native;
 
 import processing.app.Base;
 import processing.app.Preferences;
+import processing.app.ui.Theme;
 import processing.app.ui.Toolkit;
 import processing.awt.ShimAWT;
 import processing.core.PApplet;
@@ -111,13 +115,20 @@ public class DefaultPlatform {
     String laf = Preferences.get("editor.laf");
     if (laf == null || laf.length() == 0) {  // normal situation
       //UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+      // Default was 8x8, but that's not enough with the insets and rounded rect
+      // https://github.com/processing/processing4/issues/473
+      //System.out.println(UIManager.get("ScrollBar.minimumThumbSize"));
+      //UIManager.put("ScrollBar.minimumThumbSize", new Dimension(16, 24));
 
       // dummy font call so that it's registered for the LaF
       Toolkit.getSansFont(12, Font.PLAIN);
 
-      com.formdev.flatlaf.FlatLaf.registerCustomDefaultsSource("processing.app.ui");
-      UIManager.setLookAndFeel(new com.formdev.flatlaf.FlatLightLaf());
-
+      FlatLaf.registerCustomDefaultsSource("processing.app.ui");
+      //if ("dark".equals(Theme.get("laf.mode"))) {
+        //UIManager.setLookAndFeel(new FlatDarkLaf());
+      //} else {
+      UIManager.setLookAndFeel(new FlatLightLaf());
+      //}
       UIManager.put("ScrollBar.width", 16);
 
     } else {
@@ -145,11 +156,6 @@ public class DefaultPlatform {
 //      Font font = new Font(fontName, Font.PLAIN, fontSize).deriveFont(attributes);
 //      setUIFont(new FontUIResource(font));
     }
-
-    // Default was 8x8, but that's not enough with the insets and rounded rect
-    // https://github.com/processing/processing4/issues/473
-    //System.out.println(UIManager.get("ScrollBar.minimumThumbSize"));
-    UIManager.put("ScrollBar.minimumThumbSize", new Dimension(16, 24));
   }
 
 //  // Adapted from https://stackoverflow.com/a/64667581/18247494
diff --git a/build/shared/lib/theme.txt b/build/shared/lib/theme.txt
index 792fec54a..eed2cbb6d 100644
--- a/build/shared/lib/theme.txt
+++ b/build/shared/lib/theme.txt
@@ -1,6 +1,11 @@
 # The gradient.top and gradient.bottom lines are used by makeGradient(),
 # so search for makeGradient() calls to see whether they're still in use.
 
+## Look-and-Feel Entries ##
+
+laf.mode = dark
+laf.accent.color = #cc0000
+
 
 ## EditorToolbar ##
 
diff --git a/todo.txt b/todo.txt
index 23430b338..5324c9809 100755
--- a/todo.txt
+++ b/todo.txt
@@ -23,7 +23,7 @@ X   rewrite language selector to use fallback fonts
 X add manager.panel constants for colors
 X status panel not updating in updateTheme()
 X StatusPanel.getBodyStyle() has hard-coded fonts/sizes
-_ accent color and light/dark mode into the theme, and use with flatlaf
+X accent color and light/dark mode into the theme, and use with flatlaf
 _ monochrome icon for foundation
 _ icons for contrib manager list entries (green/orange PNGs won't do)
 _ remove ability to rearrange columns in contrib manager