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.

assets/css/header.css

@@ -170,6 +170,76 @@
   border-color: #c8922a;
 }
 
+/* "Use my location" and "Share" - same brass pill as the magnifier beside them */
+.utci-loc-action {
+  flex: 0 0 auto;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 28px;
+  height: 28px;
+  padding: 0;
+  border: 1.5px solid #c9b08a;
+  border-radius: 999px;
+  background: #fffcf2;
+  color: #9a7a3a;
+  cursor: pointer;
+  transition: color 0.2s, border-color 0.2s, background 0.2s, box-shadow 0.2s;
+}
+
+.utci-loc-action:hover:not(:disabled) {
+  color: #c8922a;
+  border-color: #c8922a;
+  background: #fef3dc;
+}
+
+.utci-loc-action:focus-visible {
+  outline: none;
+  border-color: #c8922a;
+  box-shadow: 0 0 0 3px #c8922a24;
+}
+
+.utci-loc-action:disabled { cursor: default; opacity: 0.6; }
+
+/* Slow pulse while the browser is resolving the fix */
+.utci-loc-action.is-busy svg { animation: loc-seek 1.1s ease-in-out infinite; }
+
+@keyframes loc-seek {
+  0%, 100% { opacity: 1; }
+  50%      { opacity: 0.35; }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .utci-loc-action.is-busy svg { animation: none; opacity: 0.55; }
+}
+
+/* Transient note under the location row: "Link copied", permission errors */
+.utci-loc-note {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  margin-top: 6px;
+  font-family: Manrope, sans-serif;
+  font-size: 11px;
+  letter-spacing: 0.04em;
+  color: #7a6a46;
+}
+
+.utci-loc-note.is-warn { color: #a8603a; }
+
+.utci-loc-note-x {
+  border: 0;
+  background: none;
+  padding: 0 2px;
+  font-size: 14px;
+  line-height: 1;
+  color: inherit;
+  cursor: pointer;
+  opacity: 0.7;
+}
+
+.utci-loc-note-x:hover { opacity: 1; }
+
 /* The lat/lon below the location */
 .utci-loc-coords {
   font-family: JetBrains Mono, monospace;