[ADD] arrows to slider

main/styleguide/source/css/atoms/heading.pcss

@@ -191,30 +191,27 @@ p {
   }
 
   .slick-arrow {
+    font-size: 0;
     position: absolute;
-    color: white;
     top: 70%;
+    right: 10%;
     z-index: 10;
-    font-size: 0;
 
     &:before, &:after {
-      border-right: 2px solid;
+      color: white;
+      border-right: 2px solid white;
+      border-bottom: 2px solid white;
       content: '';
-      display: block;
-      height: 8px;
-      margin-top: -6px;
       position: absolute;
-      transform: rotate(135deg);
-      right: 10px;
-      top: 50%;
-      width: 0;
+      width: 16px;
+      height: 16px;
     }
 
     &.slick-next {
-      right: 3%;
+      transform: rotate(-45deg);
     }
     &.slick-prev {
-      right: 8%;
+      transform: rotate(135deg);
     }
   }
   .slick-dots {