3.9

Summaries added — every column in COL_DESCRIPTIONS got a short (1–2 sentences) and a link to its reference row. Full desc text kept intact for the day-tab metric labels.
Popup rewired — renders the summary plus a "More about this column →" link, opening in a new tab.
Link styling — .col-info-more pinned below the summary so it stays visible if the text scrolls; centred on mobile with the rest.
Anchors on the reference page — 35 row ids in columns.html, one per column key.
New "Rows" row — the hour/interval header had a popup but no matching row on the reference page; added.
Landing highlight — tr:target gets a gold bar and tint, with scroll offset so the nav doesn't cover it.

profiles.html

@@ -19,7 +19,7 @@
   <meta name="twitter:image" content="https://sunscope.net/og-image.png" />
 
   <link rel="icon" type="image/svg+xml" href="./favicon.svg" />
-  <link rel="stylesheet" href="./assets/about.css?v=15a">
+  <link rel="stylesheet" href="./assets/about.css?v=15b">
 
   <script type="application/ld+json">
   {