Move content closer up to related header.

assets/sass/base/grouping/_grouping.scss

@@ -74,7 +74,7 @@ hr {
 
 p {
   // Add vertical rhythm margins.
-  @include margin-block(.375 .75);
+  @include margin-block(.75);
 
   // Set max text line width in main for readability.
   .main & {

assets/sass/base/headings/_headings.scss

@@ -28,6 +28,26 @@ h6,
   }
 }
 
+// Move content closer up to related header.
+h2,
+%h2,
+h3,
+%h3,
+h4,
+%h4,
+h5,
+%h5,
+h6,
+%h6 {
+  & + :is(p, ul, ol) {
+    @include margin-block-start(0.375);
+  }
+
+  & + & {
+    @include margin-block-start(0.5);
+  }
+}
+
 h1,
 %h1 {
   // h1 only on top of page so different margins.