Fix downloads without results

app.py

@@ -58,7 +58,7 @@ app_ui = ui.page_fluid(
                 ui.input_slider("threshold", "Threshold", 0, 1.0, 0.8),
                 ui.input_action_button("analyze", "Analyze", class_="btn-success"),
                 # ui.input_switch("mask", "Mask", False),
-                ui.column(4, ui.download_button("download", "Download Results", class_="btn-primary")),
+                ui.column(4, ui.download_button("download", "Download Results", class_="btn-success")),
                 width=300
 
             ),
@@ -220,18 +220,22 @@ def server(input, output, session: Session):
     @session.download()
     def download():
         results = analysis_results.get()
-        df = pd.DataFrame([{
-            "Filename": r["filename"],
-            "Viable": r.get("viable", ""),
-            "Non-Viable": r.get("non-viable", ""),
-            "Empty": r.get("empty", ""),
-            "Total": r.get("total", "")
-        } for r in results])
-
-        # Create in-memory CSV file
-        with tempfile.NamedTemporaryFile(delete=False, suffix=".csv") as tmp:
-            df.to_csv(tmp.name, index=False)
-            return tmp.name
+        if not results:
+            return ui.div("No results yet. Upload images and click 'Analyze'.",
+                          class_="text-muted")
+        else:
+            df = pd.DataFrame([{
+                "Filename": r["filename"],
+                "Viable": r.get("viable", ""),
+                "Non-Viable": r.get("non-viable", ""),
+                "Empty": r.get("empty", ""),
+                "Total": r.get("total", "")
+            } for r in results])
+
+            # Create in-memory CSV file
+            with tempfile.NamedTemporaryFile(delete=False, suffix=".csv") as tmp:
+                df.to_csv(tmp.name, index=False)
+                return tmp.name
 
 
 app = App(app_ui, server)

styles.css

@@ -2,10 +2,18 @@
 /* Modern sleek theme with dark mode elements */
 
 body {
-    background-color: #f8f9fa;
+    background-color: white;
     font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
 }
-
+/* Image display styling */
+img {
+    border-radius: 10px;
+    object-fit: cover;
+    max-height: 300px;
+    width: 100%;
+    margin: 10px 0;
+    /*box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);*/
+}
 .container-fluid {
     padding: 20px;
     max-width: 1400px;
@@ -63,7 +71,6 @@ body {
 
 .btn-file:hover {
     background-color: #357abd;
-    transform: translateY(-1px);
 }
 
 /* Analyze button styling */
@@ -78,7 +85,6 @@ body {
 
 .btn-success:hover {
     background-color: #219653 !important;
-    transform: translateY(-1px);
 }
 
 /* Image cards styling */
@@ -92,19 +98,7 @@ body {
     transition: transform 0.2s ease;
 }
 
-.card:hover {
-    transform: translateY(-3px);
-}
 
-/* Image display styling */
-img {
-    border-radius: 10px;
-    object-fit: cover;
-    max-height: 300px;
-    width: 100%;
-    margin: 10px 0;
-    /*box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);*/
-}
 
 /* Results text styling */
 .results-text {
@@ -118,22 +112,6 @@ img {
     border-left: 4px solid #4a90e2;
 }
 
-/* Download button styling */
-.btn-primary {
-    background-color: #2ecc71 !important;
-    right: 10px;
-    top: 10px;
-    border: none;
-    border-radius: 8px;
-    padding: 10px 25px;
-    font-weight: 600;
-    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
-}
-
-.btn-primary:hover {
-    background-color: #27ae60 !important;
-}
-
 /* Responsive design */
 @media (max-width: 768px) {
     .col-md-4 {