page/single: clear fixed navbar + APA-style entry-content card

- templates/page.html + single.html: 6.5rem top margin so the title clears the
  fixed navbar (transparent gap above the card, not padding — the entry-content
  card background now starts at the title, doesn't run to the top).
- entry-content card: 96px (1in) padding on all sides for an APA-paper look;
  consolidated from the split 30px sides + inline top/bottom into one rule.

style.css

@@ -1586,8 +1586,7 @@ h2.entry-title {
    .wp-block-post-content.entry-content. */
 .wp-block-group.entry-content {
 	background: #f6f6f6;
-	padding-left: 30px;
-	padding-right: 30px;
+	padding: 96px; /* 1in APA-style margins on all sides (96px = 1in) */
 	border-radius: 6px;
 }
 .signature {

templates/page.html

@@ -2,8 +2,8 @@
 
 <!-- wp:group {"tagName":"main","layout":{"type":"constrained"}} -->
 <main class="wp-block-group">
-	<!-- wp:group {"className":"entry-content","style":{"spacing":{"padding":{"top":"var:preset|spacing|60","bottom":"var:preset|spacing|60"}}},"layout":{"type":"constrained"}} -->
-	<div class="wp-block-group entry-content" style="padding-top:var(--wp--preset--spacing--60);padding-bottom:var(--wp--preset--spacing--60)">
+	<!-- wp:group {"className":"entry-content","style":{"spacing":{"margin":{"top":"6.5rem"}}},"layout":{"type":"constrained"}} -->
+	<div class="wp-block-group entry-content" style="margin-top:6.5rem">
 		<!-- wp:post-title {"level":1} /-->
 		<!-- wp:post-content {"layout":{"type":"constrained"}} /-->
 	</div>

templates/single.html

@@ -2,8 +2,8 @@
 
 <!-- wp:group {"tagName":"main","layout":{"type":"constrained"}} -->
 <main class="wp-block-group">
-	<!-- wp:group {"style":{"spacing":{"padding":{"top":"var:preset|spacing|60","bottom":"var:preset|spacing|60"}}},"layout":{"type":"constrained"}} -->
-	<div class="wp-block-group" style="padding-top:var(--wp--preset--spacing--60);padding-bottom:var(--wp--preset--spacing--60)">
+	<!-- wp:group {"style":{"spacing":{"margin":{"top":"6.5rem"},"padding":{"bottom":"var:preset|spacing|60"}}},"layout":{"type":"constrained"}} -->
+	<div class="wp-block-group" style="margin-top:6.5rem;padding-bottom:var(--wp--preset--spacing--60)">
 		<!-- wp:post-title {"level":1} /-->
 		<!-- wp:group {"style":{"spacing":{"margin":{"bottom":"var:preset|spacing|40"}}},"layout":{"type":"flex","flexWrap":"nowrap"}} -->
 		<div class="wp-block-group" style="margin-bottom:var(--wp--preset--spacing--40)">