Combining border-top,border-right,border-left,border-bottom in CSS

No you can't set them as single one for example if you have div{ border-top: 2px solid red; border-right: 2px solid red; border-bottom: 2px solid red; border-left: 2px solid red; } same properties for all fours then you can set them in single line

div{border:2px solid red;}