What is the default text hex color?

You're able to just write outside the bbcode by clicking on that tab. It'll change the font not inside the code back to forum default...

999999

^ or use that <3

Or, alternatively, you could just color only the text that you want colored and leave the rest alone, thus letting the system put all non-colored text to the default color like it does for every other post.

    That one actually works ^_^. All 9's is a few shades darker. 

It's cccccc