iPhone fix

apps/volume.js

@@ -23,6 +23,7 @@ const VolumeMap = {
             const dist3  = Math.max(Math.min(dist2, 1), 0)
             video.style.opacity = dist3
             video.volume = dist3
+            video.muted = !dist3  // iPhone does not allow graded volume
         }
     },
     view() {