Reduce top spacing between adjacent headings

Author: NicolaSaunders

assets-src/styles/sass/30-base/_typography.scss

@@ -25,10 +25,14 @@ h1, h2, h3, h4, h5, h6 {
  	margin-block-start: 0;
  }
 
- h2, h3, h4, h5, h6 {
-	 margin-block-start: 1em;
+ :where(h2, h3, h4, h5, h6) {
+	 margin-block-start: 2em;
  }
 
+ :where(h2, h3, h4, h5, h6) + :where(h3, h4, h5, h6) {
+	 margin-block-start: 1em;
+}
+
 :where(h1, .h1 .venus) {
 	font-size: var(--w3c-text-5);
 }