style: add more whitespace before headlines

Author: line-o

src/main/frontend/sass/_general.scss

@@ -27,22 +27,26 @@ h2 {
   color: var(--darkerprimary);
   font-weight: bold;
   font-size: 2.25rem;
+  margin-block-start: 2.25rem;
   letter-spacing: -.05em;
 }
 
 h3 {
   color: var(--darkprimary);
   font-size: 1.85rem;
+  margin-block-start: 1.85rem;
 }
 
 h4 {
   font-size: 1.2rem;
+  margin-block-start: 1.2rem;
   font-style: italic;
   font-weight: normal;
 }
 
 h5 {
   font-size: 1rem;
+  margin-block-start: 1rem;
   font-weight: normal;
 }