refactor: iOS page improvements and css fixes

1. Changed active colour of the links and buttons.
2. Fixed the issue with scrolling to the anchor point.
3. Changed content of the Pybytes iOS page

themes/doc-theme/static/js/smooth-scroll.js

@@ -0,0 +1,23 @@
+/*
+* Smooth scroll to anchor link
+*/
+
+
+$(document).ready(function(){
+    $( 'a[href^="#"]' ).on( 'click', function( e ) {
+
+        if ( this.hash !== '' ) {
+            e.preventDefault();
+
+            var hash = this.hash;
+            var nav = $( '.navbar' ).outerHeight();
+            var targetOffset = $( hash ).offset().top - nav;
+
+            $( 'html, body' ).animate( {
+                scrollTop: targetOffset
+            }, 1100, function() {
+                //window.location.hash = hash;
+            } );
+        }
+    } );
+} );