adding person introduction heading modifier

opentech/static_src/src/sass/components/_heading.scss

@@ -23,4 +23,9 @@
         margin: 10px 0;
         line-height: 1;
     }
+
+    &--person-introduction {
+        margin: 1rem 0;
+        font-weight: $weight--light;
+    }
 }