fix: ensure empty reading progress bar is always visible for articles

- Change progress bar background from transparent to border color when no progress
- Reading progress separator now always shows 1px line for articles
- Maintains visual consistency between articles with and without reading progress
- Ensures proper visual separation between content and footer

src/components/BookmarkViews/CardView.tsx

@@ -152,14 +152,14 @@ export const CardView: React.FC<CardViewProps> = ({
           </div>
         </div>
         
-        {/* Reading progress indicator as separator - always shown */}
+        {/* Reading progress indicator as separator - always shown for articles */}
         {isArticle && (
           <div className="reading-progress-separator">
             <div
               className="progress-fill"
               style={{
                 width: readingProgress ? `${Math.round(readingProgress * 100)}%` : '0%',
-                background: readingProgress ? progressColor : 'transparent'
+                background: readingProgress ? progressColor : 'var(--color-border)'
               }}
             />
           </div>