border above heading in mobile styles

src/components/heading/heading.scss

@@ -78,19 +78,21 @@
 
   &:after {
     background-color: transparent;
-    border-bottom: 1px solid var(--grayscale-dark);
+    border-bottom: 3px solid var(--grayscale-dark);
     content: ' ';
     display: flex;
     height: 2px;
     width: 100%;
     margin-left: 0;
-    margin-bottom: 1rem;
+    margin-bottom: 0.5rem;
     position: relative;
     top: 50%;
     transform: translateY(-50%);
 
     @include breakpoint($narrow) {
       margin-left: 2rem;
+      border-bottom: 1px solid var(--grayscale-dark);
+      margin-bottom: 1rem;
     }
   }
 }