CSS3的box-shadow阴影效果 浏览器参照基准：Firefox4 and Later, Chrome5 and Later, Safari5 and Later, Opera10.53 and Later, IE9.0 and Later 内阴影效果（偏移值都为正）： #box-shadow{ -moz-box-shadow:5px 5px 5px #999 inset; /* For F