Start the NPS Unigrid visual redesign

Black topbar banner with live map-center coordinates, a black header
(with NPS pictogram) on waypoint popups, offline basemap wood/park
colors unified with the online Liberty green, and the sidebar grouped
into the planned Explorer / Offline hub / Navigation menu sections.

public/js/gpx.js

@@ -916,9 +916,12 @@ function gpxFileUrl(path) {
 
 // properties come straight from an uploaded GPX file — untrusted input —
 // so every value is escaped before landing in the popup's HTML.
-function popupHtml({ name, description, time, category, photos }) {
+function popupHtml({ name, description, time, category, photos, icon }) {
   const parts = [];
-  if (name) parts.push(`<strong>${escapeHtml(name)}</strong>`);
+  if (name) {
+    const glyph = icon && POI_ICONS[icon] ? `<span class="gpx-popup__header-icon">${POI_ICONS[icon]}</span>` : "";
+    parts.push(`<div class="gpx-popup__header"><strong>${escapeHtml(name)}</strong>${glyph}</div>`);
+  }
   if (category) parts.push(`<p class="gpx-popup__category">${escapeHtml(category)}</p>`);
   if (photos?.length > 0) parts.push(formatPhotos(photos));
   if (description) parts.push(formatDescription(description));