判断设备是纵向还是横向：
纵向：@media all and (orientation : landscape)
横向：@media all and (orientation : portrait)
强制横屏：在判断是纵向之后加入：
transform: rotate(90deg);
transform-origin: left bottom;
-ms-transform: rotate(90deg); /* Internet Explorer 9 */
-ms-transform-origin: left bottom; /* Internet Explorer 9 */
-moz-transform: rotate(90deg); /* Firefox */
-moz-transform-origin: left bottom; /* Firefox */
-webkit-transform: rotate(90deg); /* Safari & Chrome */
-webkit-transform-origin: left bottom; /* Safari & Chrome */
-o-transform: rotate(90deg); /* Opera */
-o-transform-origin: left bottom; /* Opera */