关于HTML，css3自适应屏幕，自适应宽度

设置了在不同分辨率下，显示的css样式：

@media screen and (min-width:1080px){
  .box{ width: 1080px;}.content{width: 1040px;}
  .img{height:180px;}
  .img{font-size: 48px;line-height: 180px;}
  .title{font-size: 46px;line-height: 100px;}
  .detail{font-size: 20px;}
}

@media screen and (min-width: 900px) and (max-width: 1079px) {
  .box{ width: 900px; }.content{width: 860px;}
  .img{height:160px;}
  .img{font-size: 40px;line-height: 160px;}
  .title{font-size: 38px;line-height: 80px;}
  .detail{font-size: 17px;}
}
@media screen and (min-width: 768px) and (max-width: 899px) {
  .box{ width: 768px; }.content{width: 728px;}
  .img{height:140px;}
  .img{font-size: 32px;line-height: 140px;}
  .title{font-size: 30px;line-height: 60px;}
  .detail{font-size: 14px;}
}
@media only screen and (min-width: 480px) and (max-width: 767px){
   .box{ width: 480px; }.content{width: 440px; }
  .img{height:98px;}
  .img{font-size: 24px;line-height: 100px;}
  .title{font-size: 22px;line-height: 40px;}
  .detail{font-size: 11px;}
}
@media only screen and (max-width: 479px) {
  .box{ width: 300px; }.content{width: 300px;}
  .img{height:60px;}
  .img{font-size: 16px;line-height: 60px;}
  .title{font-size: 14px;line-height: 20px;}
  .detail{font-size: 8px;}
}

要是刚好在那个宽度上，如：屏幕宽度900，刚好