移动端开发--参考京东（屏幕范围）

@media screen and (max-width: 320px) {
}
@media screen and (min-width: 321px) and (max-width: 374px) {
}
@media screen and (min-width: 375px) and (max-width: 413px) {
}
@media screen and (min-width: 414px) and (max-width: 559px) {
}
@media screen and (min-width: 560px) and (max-width: 639px) {
}
@media screen and (min-width: 640px) {
}