bootstrap不同屏幕区分数值
@media (min-width:1200px){
}
@media (min-width:992px) and (max-width:1199px){
}
@media (min-width:768px) and (max-width:991px){
}
@media (max-width:767px){
}
@media (min-width:1200px){
}
@media (min-width:992px) and (max-width:1199px){
}
@media (min-width:768px) and (max-width:991px){
}
@media (max-width:767px){
}