Move color mode from offline servicing to firstrun

functions/microwin/Microwin-NewFirstRun.ps1

@@ -103,6 +103,35 @@ function Microwin-NewFirstRun {
     reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Start" /v ShowRecentList /t REG_DWORD /d 0 /f
     reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v Start_TrackDocs /t REG_DWORD /d 0 /f
 
+    # Color Modes -- requires sending messages to apply to everything
+    reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize" /v "AppsUseLightTheme" /t REG_DWORD /d 0 /f
+    reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize" /v "SystemUsesLightTheme" /t REG_DWORD /d 0 /f
+
+    # Send the WM_SETTINGCHANGE message to all windows
+    Add-Type -TypeDefinition @"
+using System;
+using System.Runtime.InteropServices;
+public class Win32 {
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
+    public static extern IntPtr SendMessageTimeout(
+        IntPtr hWnd,
+        uint Msg,
+        IntPtr wParam,
+        string lParam,
+        uint fuFlags,
+        uint uTimeout,
+        out IntPtr lpdwResult);
+}
+"@
+
+    $HWND_BROADCAST = [IntPtr]0xffff
+    $WM_SETTINGCHANGE = 0x1A
+    $SMTO_ABORTIFHUNG = 0x2
+    $timeout = 100
+
+    # Send the broadcast message to all windows
+    [Win32]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE, [IntPtr]::Zero, "ImmersiveColorSet", $SMTO_ABORTIFHUNG, $timeout, [ref]([IntPtr]::Zero))
+
     Clear-Host
     Write-Host "The taskbar will take around a minute to show up, but you can start using your computer now. Try pressing the Windows key to open the Start menu, or Windows + E to launch File Explorer."
     Start-Sleep -Seconds 10