Is it bad practice to comment out single lines of CSS with //?

Question

I have recently started using // to \"comment\" out single lines of CSS code. I understand that I am not actually commenting out the line; I am just breaking it

Answer 1

Just to add some further information and confirming the "only use /* comments" rule. A customer who has access to the website folder just choose by himself to comment out a single line using this:

//*  comment here   *//

Actually Chrome and Safari will ignore ANYTHING that follows this line; I would call it a "CSS killer".