code for arrows in pure LESS

arrows.less

//arrows
@arrowColor: gray;
@arrowSize: 10px;

.arrowUp, .arrowDown, .arrowRight, .arrowLeft {
	width: 0;
	height: 0;
}

.arrowUp, .arrowDown {
	border-left: @arrowSize solid transparent;
	border-right: @arrowSize solid transparent;
}

.arrowRight, .arrowLeft {
	border-top: @arrowSize solid transparent;
	border-bottom: @arrowSize solid transparent;
}

.arrowUp {
	border-bottom: @arrowSize solid @arrowColor;
}

.arrowDown {
	border-top: @arrowSize solid @arrowColor;
}

.arrowRight {
	border-left: @arrowSize solid @arrowColor;
}

.arrowLeft {
	border-right:@arrowSize solid @arrowColor;
}