How to hide Android WebView scrollbars?

I'm using the Median.co to build apk for my web-app. Currently facing some issues if anyone can help me please

Is there a setting to hide Android WebView scrollbars? I tried every thing and the Scrollbars aren't visible on any browser but when using the apk, it is back again.
When fullscreen mode is enabled, the Android back button requires two presses to navigate. First press exits fullscreen, second navigates. How do I hide the status bar without this double back press issue?
And enabling transparent status bar turns the status bar in gery colors.

Anyone please help me. Thankyou.