移動端媒體查詢適配

主要用於移動端內容適配，因爲移動端有時候須要根據高度來進行適配，好比iPhone4和iPhone5的寬度同樣，可是高度不一樣

/*iphone4*/
@media only screen and (max-width: 320px) and (max-width: 480px) {
html,body{
font-size: 12px;
}
}
/*iphone5*/
@media only screen and (max-width: 320px) and (min-height: 568px) {
html,body{
font-size: 14px;
}
}
/*ihpne6,7,8*/
@media only screen and (min-width: 375px) and (max-width: 413px) {
html,body{
font-size: 16px;
}
}
/*ihpne6,7,8Plus*/
@media only screen and (min-width: 414px) and (max-width: 640px) {
html,body{
font-size: 18px;
}
}