Is having a long CSS selector bad?

Question

Is a selector like

.a, .b, .c, .d, .e, .f, .g, .h, ......... , .zzzzz {font-size:16px}

bad for performance? If yes how and if no why?

I Googled and read a lot of posts including the ones by Mozilla and couldn't find any mention of having a large number of class names as a selector being bad.

Answer 1

No, there is no performance problem here.

What is bad is a long selector involving many checks but your selector is in fact a sequence of selectors, equivalent to

 .a {font-size:16px}
 .b {font-size:16px}
  ...

Selectors with just a class are among the most efficient ones.

There's no real problem, even if you probably should have less classes in order to manage your code more easily.

Answer 2

This is the valid syntax for assigning a common properties to multiple classes at a time. there is no down side effect.