Feature request: Styled alert boxes CSS + link color

Hey guys

I would be helpful if the styled notification boxes would have following features:

1. Css classes for success, warning, danger: Otherwise we cannot apply custom styles to all boxes
2. Link color: the alert boxes have default link color. It would be better to have link color in same style as the box.
3. Add 4th box: yellow color, warning

I think those additons are super benefical for all users

Keep up the good work guys, it’s a great plugin