diff --git a/src/window.vala b/src/window.vala
index 9bbe6f1..c5eea4b 100644
--- a/src/window.vala
+++ b/src/window.vala
@@ -1,6 +1,8 @@
 public class WriteAs.MainWindow : Gtk.ApplicationWindow {
     private Gtk.TextView canvas;
 
+    private bool dark_mode = false;
+
     construct {
         construct_toolbar();
 
@@ -31,7 +33,28 @@ public class WriteAs.MainWindow : Gtk.ApplicationWindow {
         var settings = Gtk.Settings.get_default();
         darkmode_button.toggled.connect(() => {
             settings.gtk_application_prefer_dark_theme = darkmode_button.active;
+            dark_mode = darkmode_button.active;
+            adjust_text_style();
         });
         header.pack_end(darkmode_button);
     }
+
+    private Gtk.CssProvider cur_styles = null;
+    private void adjust_text_style() {
+        try {
+            var styles = canvas.get_style_context();
+            if (cur_styles != null) styles.remove_provider(cur_styles);
+
+            var css = "";
+            if (dark_mode) {
+                css = "* {background: black; color: white;}";
+            }
+            cur_styles = new Gtk.CssProvider();
+            cur_styles.load_from_data(css);
+
+            styles.add_provider(cur_styles, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
+        } catch (Error e) {
+            warning(e.message);
+        }
+    }
 }