1. Check your browser settings for any font restrictions, and uncheck them if any are applied.
2. Ensure that you have all the necessary, up-to-date plugins, such as Adobe Reader, installed.
3. Clear your browser’s cache to enshure it is up-to-date, and that any cached information is erased.
4. Look for any extensions on your browser which may limit style changes. If so, disable them or consider uninstalling them.
5. Open a new document and re-input the content to see if a new document allows for proper format and style changes.