Building 4 edges solution basing on @Eagorajose's answer with shorthand syntax:
background: linear-gradient(to right, #000 33%, #fff 0%) top/10px 1px repeat-x, /* top */
linear-gradient(#000 33%, #fff 0%) right/1px 10px repeat-y, /* right */
linear-gradient(to right, #000 33%, #fff 0%) bottom/10px 1px repeat-x, /* bottom */
linear-gradient(#000 33%, #fff 0%) left/1px 10px repeat-y; /* left */
#page {_x000D_
background: linear-gradient(to right, #000 33%, #fff 0%) top/10px 1px repeat-x, /* top */_x000D_
linear-gradient(#000 33%, #fff 0%) right/1px 10px repeat-y, /* right */_x000D_
linear-gradient(to right, #000 33%, #fff 0%) bottom/10px 1px repeat-x, /* bottom */_x000D_
linear-gradient(#000 33%, #fff 0%) left/1px 10px repeat-y; /* left */_x000D_
_x000D_
width: 100px;_x000D_
height: 100px;_x000D_
}
_x000D_
<div id="page"></div>
_x000D_