border-width: 1px 2px 2px;
border-style: solid dashed dotted;
border-color:red green blue;
/*分别为 上→左右→下 边框设置*/

border: 1px solid #fff

/*border: 1px solid red; /*复合样式*/

border-width: 1px 2px 2px 1px;
border-style: solid dashed dotted solid;
border-color:red green blue pink;
/*分别为上→右→下→左 边框设置*/

border-width: 1px 2px;
border-style: solid dashed;
border-color:red green;
/*分别为 上下 左右 边框设置*/

border-top;
border-right;
border-bottom;
border-left;