Question

How can I do the Title without using :not selector or overriding?

PS. I’m also curious how can I do this with :not selector. I tried this but didn’t work:

#div1 #div2 img:not[.c1]{ ... }

Answer 1

If you don’t want to use :not, you should be able to use:

#div1 #div2 img { /* things that apply to :not(.c1) */ }
#div1 #div2 img.c1 { /* adjustments for .c1 */ }

Your syntax for :not is a bit off. From the fine manual:

The negation pseudo-class, :not(X), is a functional notation taking a simple selector (excluding the negation pseudo-class itself) as an argument. It represents an element that is not represented by its argument.

A class selector is a simple selector so this should work:

#div1 #div2 img:not(.c1) { ... }