border-image
by Nikaple
HTML
<div></div>
SCSS
$red: rgb(217, 84, 66);
$blue: rgb(104, 165, 245);
div {
width: 200px;
height: 120px;
border: 1px solid transparent;
border-image: 2 repeating-linear-gradient(-45deg, $red 0, $red 10px, transparent 0, transparent, 20px, $blue 0, $blue 30px, transparent 0, transparent 40px);
}