微信小程序 基础知识css样式media标签

<link href="styles/main.css" rel="external nofollow" rel="stylesheet" type="text/css" media="screen" />
<link href="styles/print.css" rel="external nofollow" rel="stylesheet" type="text/css" media="print" /> 
<link href="main.css" rel="external nofollow" rel="stylesheet" type="text/css" media="all'/>

@media all { 
        body{ font:12px; width:100%;} 
   } 

@media print 
{ 
  body{ font:14px; width:595px;}  /* 用于打印时将宽度设置为595px(A4) */ 
} 

@media all and (min-width: 1001px) { 
 #sidebar ul li a:after { 
  content: " (" attr(data-email) ")"; 
  font-size: 11px; 
  font-style: italic; 
  color: #666; 
 } 
} 

@media all and (max-width: 1000px) and (min-width: 700px) { 
 #sidebar ul li a:before { 
  content: "Email: "; 
  font-style: italic; 
  color: #666; 
 } 
} 

@media all and (max-width: 699px) and (min-width: 520px), (min-width: 1151px) { 
 #sidebar ul li a { 
  padding-left: 21px; 
  background: url(../images/email.png) left center no-repeat; 
 } 
} 

@media screen and (-webkit-min-device-pixel-ratio: 1.0), screen and (min--moz-device-pixel-ratio: 1.0), screen and (min-device-pixel-ratio: 1.0), screen and (min-resolution: 1.0dppx) {
  .icon-del {
background-image: url(../../resources/images/ui_3@2x.png);
background-size: 274px 228px;
display: block;
 }
}