Add box shadow

src/display/css_html_js.py

@@ -233,7 +233,10 @@ custom_css = """
 }
 
 .intro-block {
-    padding: 20px;
+    background-color: #f5f5f5;
+    padding: 1.5rem;
+    border-radius: 10px;
+    box-shadow: 0px 4px 10px rgba(0, 0, 0, 0.05);
 }
 
 .header-row {