Vanessa219/vditor#719

I think this is not GFM spec.
if not, I want to suggest the new spec.

For font size, font, text color, background color
[]{:.intro.red.fontsize#id.class}

For paragraph
{:.center}

This is not the standard, but when you support this kind of syntax, The Vditor seems to be competitive with other wysiwyg editors.(froala, ckeditor etc.)

You can also export as standard GFM spec.

@jakekwak Yes, we will gradually introduce more extended syntax.

@88250 Here is some comparison chart