/* 移动端 */
@media screen and (max-width: 420px) {
    .test{
        background-color: brown;
    }
    .ipad, .pc{
        display: none;
    }
}
/* ipad端 */
@media screen and (min-width: 421px) and (max-width: 1039px) {
    .test{
        background-color: aqua;
    }
    .mobile, .pc{
        display: none;
    }
}
/* pc端 */
@media screen and (min-width: 1040px) {
    .test{
        background-color: black;
    }
    .mobile, .ipad{
        display: none;
    }
}