Update app.py

app.py

@@ -78,7 +78,7 @@ accu=10
 
 # ui data
 
-css="""
+css="".join(["""
 input, input::placeholder {
     text-align: center !important;
 }
@@ -97,7 +97,7 @@ footer {
     max-width: 15cm;
 }
 .image-container {
-    aspect-ratio: """+str(width)+"/"+str(height)+""" !important;
+    aspect-ratio: """,str(width),"/",str(height),""" !important;
 }
 .dropdown-arrow {
     display: none !important;
@@ -110,7 +110,7 @@ footer {
 .btn {
     display: flex;
 }
-"""
+"""])
 
 js="""
 function custom(){