How does @media work?

Question

css

What is the difference between this declaration:

@media (max-width: 768px) {
    .content {
        width: 500px;
    }
}

and like this:

@media screen and (max-width: 768px) {
    .content {
        width: 500px;
    }
}

Answer 1

An unspecified type means all :

@media (max-width: 768px) {...}
@media all and (max-width: 768px) {...}

Answer 2

The second is only for monitor screens. Will not apply to TVs, projectors, printing, smartphones (ios and android 100% don't care about handled).