bugfix: extend swipe listener to swipe on empty space

vue/src/components/RssFeeds.vue

@@ -367,6 +367,13 @@ onMounted(async () => {
   align-items: center;
   padding-top: 1em;
   padding-bottom: 5rem;
+  /* Fill the viewport below the fixed header even when the article content
+     is short, so swipe-to-navigate works anywhere on screen instead of only
+     over the (possibly small) content area. dvh is the accurate unit on
+     mobile, where this matters most; vh is the fallback for browsers
+     without dvh support. */
+  min-height: calc(100vh - var(--app-nav-height, 4.5rem));
+  min-height: calc(100dvh - var(--app-nav-height, 4.5rem));
 }
 
 .article-feature {