心血来潮 什么都不说 上代码
.gradualChange{ width: 300px; height: 300px; border:20px solid; //兼容 border-image: -webkit-linear-gradient(#000,#333,#000) 30 30; border-image: -moz-linear-gradient(#000,#333,#000) 30 30; border-image: linear-gradient(#000,#333,#000) 30 30; }