There are plenty of languages using different comment styles, but that is beside the point. I just wanted to share an alternative I find myself using when playing around with temporary CSS, which kind of simulates the // comments.
.something {
margin-bottom: 0px; /* */
/* background-color: blue; /* */
}
By adding /* */ at the end of the line, with or without text inside, I can use /* at the front to comment out that line rather easily.
Only caveat is if you want to comment out the entire section as that end text will end any comment section, but if I want to do that, I usually just add a letter or two to disqualify the selector at the front.