how to change only for mobile view css code example

Example: css different sreen size

/* For Mobile */
@media screen and (max-width: 540px) {
    .view {
        width: 400px;
    }
}

/* For Tablets */
@media screen and (min-width: 540px) and (max-width: 780px) {
    .view {
        width: 600px;
    }
}