Why does Hermione hug malfoy?

It must be part of some dark magical ritual that we Muggles do not understand.
Or it is to express feelings like friendship and concern.
(Note: I don't remember Hermione actually kissing Harry; there is no romance between them.)

She hugged him once he finished the first challenge because he almost drowned in the ocean. She kissed him on the head because she was happy he was still alive. There is no romance between them though.