border($border-width = 1px, $border-color = #ccc, $border-style = solid, $radius = 0)

   // 为边框位置提供定位参考

   position: relative;

   if $border-width == null

     $border-width: 0;

   border-radius: $radius;

   &::after

     // 用以解决边框layer遮盖内容

     pointer-events: none;

     position: absolute;

     z-index: 999;

     top: 0;

     left: 0;

     // fix当元素宽度出现小数时，边框可能显示不全的问题

     // overflow: hidden;

     content: "\0020";

     border-color: $border-color;

     border-style: $border-style;

     border-width: $border-width;

     // 适配dpr进行缩放

     @media (max--moz-device-pixel-ratio: 1.49), (-webkit-max-device-pixel-ratio: 1.49),
　　　　　　    (max-device-pixel-ratio: 1.49), (max-resolution: 143dpi), (max-resolution: 1.49dppx)

       width: 100%;

       height: 100%;

       if $radius != null {

         border-radius: $radius;

       }

     @media (min--moz-device-pixel-ratio: 1.5) and (max--moz-device-pixel-ratio: 2.49), 
　　　　　　　　 (-webkit-min-device-pixel-ratio: 1.5) and (-webkit-max-device-pixel-ratio: 2.49),
　　　　　　　　 (min-device-pixel-ratio: 1.5) and (max-device-pixel-ratio: 2.49),
　　　　　　　　(min-resolution: 144dpi) and (max-resolution: 239dpi),
　　　　　　　　(min-resolution: 1.5dppx) and (max-resolution: 2.49dppx)

       width: 200%;

       height: 200%;

       transform: scale(.5)

       if $radius != null {

         border-radius: $radius * 2;

       }

     @media (min--moz-device-pixel-ratio: 2.5), (-webkit-min-device-pixel-ratio: 2.5),
　　　　　　　　 (min-device-pixel-ratio: 2.5),(min-resolution: 240dpi),(min-resolution: 2.5dppx)

       width: 300%;

       height: 300%;

       transform: scale(.33333)

       if $radius != null {

         border-radius: $radius * 3;

       }

     transform-origin: 0 0;

 wrap($is-wrap = true)

   if $is-wrap == true

     word-wrap: break-word;

     word-break: break-all;

   else

     white-space: nowrap;

 ellipsis($width = null, $line-clamp = 1)

   overflow: hidden;

   text-overflow: ellipsis;

   width: $width;

   if abs($line-clamp) > 1

     // 要使得多行截取生效，display的值只能为-webkit-box

     display: -webkit-box !important;

     -webkit-line-clamp: $line-clamp;

     flex-direction column

     wrap()

   else

     wrap(false)