SetWindowTheme

[DllImport("uxtheme.dll", SetLastError = true)]
public static extern HRESULT SetWindowTheme(
   HWND hwnd,
   [MarshalAs(UnmanagedType.LPWStr)] string pszSubAppName,
   [MarshalAs(UnmanagedType.LPWStr)] string pszSubIdList
);

Microsoft documentation: Link