diff --git a/src/apprt/gtk/App.zig b/src/apprt/gtk/App.zig
index e98c58089..6a1c089e5 100644
--- a/src/apprt/gtk/App.zig
+++ b/src/apprt/gtk/App.zig
@@ -1002,13 +1002,19 @@ fn loadRuntimeCss(
             \\  color: rgb({[r]d},{[g]d},{[b]d});
             \\  background: rgb({[r]d},{[g]d},{[b]d});
             \\}}
-        ,
-            .{
-                .r = color.r,
-                .g = color.g,
-                .b = color.b,
-            },
-        );
+        , .{
+            .r = color.r,
+            .g = color.g,
+            .b = color.b,
+        });
+    }
+
+    if (config.@"window-title-font-family") |font_family| {
+        try writer.print(
+            \\.window headerbar {{
+            \\  font-family: "{[font_family]s}";
+            \\}}
+        , .{ .font_family = font_family });
     }
 
     if (version.atLeast(4, 16, 0)) {
diff --git a/src/apprt/gtk/ClipboardConfirmationWindow.zig b/src/apprt/gtk/ClipboardConfirmationWindow.zig
index b6db7c5ef..a04271497 100644
--- a/src/apprt/gtk/ClipboardConfirmationWindow.zig
+++ b/src/apprt/gtk/ClipboardConfirmationWindow.zig
@@ -64,6 +64,7 @@ fn init(
     c.gtk_window_set_title(gtk_window, titleText(request));
     c.gtk_window_set_default_size(gtk_window, 550, 275);
     c.gtk_window_set_resizable(gtk_window, 0);
+    c.gtk_widget_add_css_class(@ptrCast(@alignCast(gtk_window)), "window");
     c.gtk_widget_add_css_class(@ptrCast(@alignCast(gtk_window)), "clipboard-confirmation-window");
     _ = c.g_signal_connect_data(
         window,
diff --git a/src/apprt/gtk/ConfigErrorsWindow.zig b/src/apprt/gtk/ConfigErrorsWindow.zig
index ff2791997..5fbf8e835 100644
--- a/src/apprt/gtk/ConfigErrorsWindow.zig
+++ b/src/apprt/gtk/ConfigErrorsWindow.zig
@@ -55,6 +55,7 @@ fn init(self: *ConfigErrors, app: *App) !void {
     c.gtk_window_set_default_size(gtk_window, 600, 275);
     c.gtk_window_set_resizable(gtk_window, 0);
     c.gtk_window_set_icon_name(gtk_window, build_config.bundle_id);
+    c.gtk_widget_add_css_class(@ptrCast(@alignCast(gtk_window)), "window");
     c.gtk_widget_add_css_class(@ptrCast(@alignCast(gtk_window)), "config-errors-window");
     _ = c.g_signal_connect_data(window, "destroy", c.G_CALLBACK(&gtkDestroy), self, null, c.G_CONNECT_DEFAULT);
 
diff --git a/src/apprt/gtk/Window.zig b/src/apprt/gtk/Window.zig
index 516ea7fc5..fecd05dbd 100644
--- a/src/apprt/gtk/Window.zig
+++ b/src/apprt/gtk/Window.zig
@@ -99,6 +99,7 @@ pub fn init(self: *Window, app: *App) !void {
     self.window = gtk_window;
     c.gtk_window_set_title(gtk_window, "Ghostty");
     c.gtk_window_set_default_size(gtk_window, 1000, 600);
+    c.gtk_widget_add_css_class(@ptrCast(gtk_window), "window");
     c.gtk_widget_add_css_class(@ptrCast(gtk_window), "terminal-window");
 
     // GTK4 grabs F10 input by default to focus the menubar icon. We want
diff --git a/src/apprt/gtk/inspector.zig b/src/apprt/gtk/inspector.zig
index 0c5514ce8..558175751 100644
--- a/src/apprt/gtk/inspector.zig
+++ b/src/apprt/gtk/inspector.zig
@@ -143,6 +143,7 @@ const Window = struct {
         c.gtk_window_set_title(gtk_window, "Ghostty: Terminal Inspector");
         c.gtk_window_set_default_size(gtk_window, 1000, 600);
         c.gtk_window_set_icon_name(gtk_window, build_config.bundle_id);
+        c.gtk_widget_add_css_class(@ptrCast(@alignCast(gtk_window)), "window");
         c.gtk_widget_add_css_class(@ptrCast(@alignCast(gtk_window)), "inspector-window");
 
         // Initialize our imgui widget
diff --git a/src/config/Config.zig b/src/config/Config.zig
index cade03734..615efe7a0 100644
--- a/src/config/Config.zig
+++ b/src/config/Config.zig
@@ -1077,7 +1077,10 @@ keybind: Keybinds = .{},
 
 /// The font that will be used for the application's window and tab titles.
 ///
-/// This is currently only supported on macOS.
+/// If this setting is left unset, the system default font will be used.
+///
+/// Note: any font available on the system may be used, this font is not
+/// required to be a fixed-width font.
 @"window-title-font-family": ?[:0]const u8 = null,
 
 /// The theme to use for the windows. Valid values: