Consistent style for h1 in article, aside, nav, section

See whatwg/html#7867

Author: zcorpan

micro-css-reset.css

@@ -6,6 +6,12 @@ body { margin: 0 }
 
 h1, h2, h3, h4, h5, h6 { font-weight: normal }
 
+h1
+{
+ margin-block: 0.67em;
+ font-size: 2em
+}
+
 table
 {
  border-collapse: collapse;