Update app.py

app.py

@@ -8,8 +8,12 @@ import keras_nlp
 css = """
 body {
     margin: 0;
-    height: 100%;
+    height: 100vh;
+    display: flex;
+    align-items: center;
+    justify-content: center;
 }
+
 body::before {
     content: '';
     position: fixed;