Update app.py

app.py

@@ -469,10 +469,55 @@ def build_ui():
 </div>
 """)
 
-        with gr.Row():
-            with gr.Column(scale=1):
-                use_case = gr.Dropdown(USE_CASES, value=USE_CASES[0], label="Use case")
+/* Use-case chooser as cards */
+#uc [role="radiogroup"] {
+  display: grid;
+  grid-template-columns: repeat(3, minmax(0,1fr));
+  gap: 12px;
+}
+@media (max-width: 820px) {
+  #uc [role="radiogroup"] { grid-template-columns: 1fr; }
+}
+#uc [role="radiogroup"] label {
+  border: 1px solid #eef2f7;
+  border-radius: 16px;
+  background: #fff;
+  padding: 14px 16px;
+  box-shadow: 0 8px 24px rgba(0,0,0,.06);
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  transition: transform .06s ease, box-shadow .12s ease, border-color .12s ease;
+}
+#uc [role="radiogroup"] input[type="radio"] {
+  accent-color: #14b8a6; /* teal */
+}
+#uc [role="radiogroup"] label:hover {
+  transform: translateY(-1px);
+  box-shadow: 0 12px 28px rgba(0,0,0,.10);
+}
+#uc [role="radiogroup"] input[type="radio"]:checked + span {
+  font-weight: 700;
+}
+#uc .uc-hint {
+  margin-top: 6px;
+  opacity: .7;
+  font-size: .9em;
+}
 
+        with gr.Row():
+            with gr.Column(elem_id="uc"):
+    gr.Markdown("### Choose your use case")
+    use_case = gr.Radio(
+        USE_CASES,
+        value=USE_CASES[0],
+        label=None,
+        interactive=True
+    )
+    gr.Markdown(
+        "<div class='uc-hint'>Pick one to load the matching calculator. You can switch anytime.</div>"
+    )
                 # --- MMG Inputs ---
                 mmg_monthly_volume = gr.Slider(0, 20000, 7500, step=50, label="Monthly volume (MMG)", info="Mammography exams per month", visible=True)
                 mmg_read_minutes   = gr.Number(label="Avg reading time today (minutes)", value=1.7, visible=True)