if widget is not previewable, then give the user the possibility to download it there

lib/attachmentWidget.dart

@@ -1,5 +1,6 @@
 import "dart:typed_data";
 
+import "package:crab_ui/attachmentDownload.dart";
 import "package:crab_ui/structs.dart";
 import "package:flutter/material.dart";
 import 'package:pdfrx/pdfrx.dart';
@@ -27,11 +28,42 @@ class AttachmentWidget extends StatelessWidget {
           ));
     }
     return Center(
-        child: Text(
-      "Attachment not supported for preview, you'll need to download",
-      style: TextStyle(
-          color: Colors.black, fontSize: 20, decoration: TextDecoration.none),
-    ));
+        child: Container(
+          padding: EdgeInsets.all(20),
+          decoration: BoxDecoration(
+            color: Color(0xff6C63FF),
+            borderRadius: BorderRadius.circular(16),
+            boxShadow: [
+              BoxShadow(
+                color: Colors.black26,
+                blurRadius: 10,
+              ),
+            ],       
+          ),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Text(
+                "No preview available",
+                style: TextStyle(
+                  color: Colors.white, fontSize: 18, decoration: TextDecoration.none),
+              ),
+              SizedBox(
+                height: 5,
+              ),
+              GestureDetector(
+                child: ElevatedButton(
+                  child: Row(
+                    mainAxisSize: MainAxisSize.min,
+                    children: [
+                      Text("Download", style: TextStyle(color: Color(0xff2c3e50)),),
+                      Icon(Icons.download,
+                      color: Color(0xffb0b0b0),),
+                  ]),
+                  onPressed: () => Attachmentdownload().saveFile(att),
+              )),
+              ]),
+        ));
   }
 
   @override