outline: rgba(50,50,50,0.5) solid 10px
宽度为10的灰色实线轮廓
outline: rgba(50,50,50,0.5) groove 16px
宽度为16的灰色凹槽线轮廓
outline: rgba(50,50,50,0.5) ridge 16px
宽度为16的灰色凸槽线轮廓
outline: rgba(50,50,50,0.5) ridge 10px;outline-offset:10px;
宽度为10、偏移距也为10的灰色虚线轮廓