pc打开手机站提示切换为手机屏幕

.turn {
    position: absolute;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
    background: url(../images.png) center center no-repeat #000;
    background-size: contain;
    display: none;
    z-index: 505;
}

@media ( orientation: landscape ) {
    .turn {
        display: block;
    }
}

<!--如果是横屏或电脑打开，提示它换成手机竖屏。-->
<div class="turn"></div>