LibreOffice - unlike Microsoft Word - does not offer to change the color of Arabic diacritical marks (tashkeel/harakat). However, there are two tricks.
Arabic keyboards lack many important special characters. Here is a list of the most important characters and signs which you can copy and paste.
The word Allah is often written like a calligraphy - with the dagger Aleph. There are several ways to achieve that in Microsoft Word or Libre Office.
Arabic fonts always look too small and unreadable on the browser. There are extensions for Chrome, Firefox and Opera that fix that. One is Wudooh.