How to indent in Facebook post/comment on OS X

1. Put your cursor on the text box of the post/comment you want to indent
2. Go to the menubar at the top of the screen
3. Edit > Emoji & Symbols
4. On Characters window, click setting icon. It's a gear nearly the top-left of the window, close to 3 color buttons.
5. Choose Customize Lists...
6. Choose Code Tables > Unicode and Done
7. Go to Unicode section at the end of the most left panel of Characters window
8. Look for the character number 3000. It's called "IDEOGRAPHIC SPACE"
9. Double click on that character to insert it to your text box. You can insert it as many characters as you want.
10. Save your post/comment. This empty space should help you indent your text properly.
11. You can add this character to Favorites section by click "Add to Favorites" button under the thumbnail of the character in the right most panel of the Characters window.
12. Or you can just go to "Frequently Used" section and the character should already be there.

Reference: http://webapps.stackexchange.com/questions/73433/bulleted-list-with-indentation-in-facebook-comments