how to use inherit??

Question

in letter spacing..
how to inherit from a parent class

Answer 1

The inherit keyword specifies that a property should inherit its value from its parent element.

The inherit keyword can be used for any CSS property, and on any HTML element.

For example:
span {
    color: blue;
}

.extra span {
    color: inherit;
}

Answer 2

why adding .extra span. and not .span