Hide navbar in mobile view and set box height to full viewport height.

css/converse.css

@@ -1265,7 +1265,7 @@
       #conversejs .chatbox .box-flyout {
         height: 400px;
         width: 100%;
-        height: 88vh; } }
+        height: 99vh; } }
   #conversejs .chatbox .chat-title {
     color: white;
     line-height: 15px;

css/theme.css

@@ -103,6 +103,13 @@ a:focus {
     border-bottom: 1px solid rgba(255, 255, 255, 0.3);
   }
 }
+@media (max-width: 480px) {
+    .navbar {
+        display: none;
+    }
+}
+
+
 .features-section,
 .outro,
 .intro {

sass/_chatbox.scss

@@ -73,7 +73,7 @@
             @media screen and (max-width: $mobile-landscape-length) {
                 height: $mobile-chat-height;
                 width: $mobile-chat-width;
-                height: 88vh;
+                height: 99vh;
             }
         }
         .chat-title {