what do square brackets within a css style do?

Question

I'm editing a site I inherited and I see a css syntax I don't recognize.

Has anyone ever seen this syntax before? What do the square brackets within a style mean?

Thanks, Rob

.trigger-txt-left {
 color: #0455A3;
 font-family: 'OpenSans';
 float: left;
 font-size: 16px;
 font-weight: bolder;
 width: 235px;

[font-family: 'OpenSans';
 font-family: 'HelveticaNeue-Bold';]
[font-weight: bolder;
 font-weight: normal;]
}

Answer 1

The short answer is, nothing. They aren't valid CSS.

Speculating though, perhaps the person was using some code to choose the right one somewhere else, for instance, some PHP might be reading this, then parsing out the [ and ] and then selecting the correct property.

Alternatively they might not have realised to use the /* */ style comments, or perhaps they thought they were being clever by ensuring it wasn't valid in that way.

More likely though it's a mistake, possibly copy and pasted from somewhere.