:not(s)

:not(s) – pseudo class, negation

It takes simple selector “s” as an argument and matches an element that is not represented by this argument (“s”).

Argument “s” must not contain another negation selector.

Examples

p:not(.blue) {
    color:red;
}
p:not(:first-child) {
    background:blue;
}

This code selects all paragraphs except the one(s) which are first child.

button:not([disabled]) {
    color:black;
}

This code selects all buttons except disabled.

li:not(:first-child):not(:last-child) {
    background:pink;	
}

This selects all li except first and last child of ul.

input:not([type="submit"]) {
    border:3px solid red;
}

This selects all inputs except inputs type submits.

p:not([class*='super-']) {
    background:red;
}

This selects all paragraphs witch class do not contain “super-” expression.

Resources:

MDN