With recent developments in HTML5 and CSS3, the balance has switched in favour of using web standards for mobile applications rather than native code. This has huge advantages, not least because (a) you no longer need to go invest the time and expense of getting your course approved by the respective app store, and (b) you can update your application any time you like and your users will see the changes almost immediately. The course starts with a refresher on the new semantic elements of HTML5. Use of these is strongly advocated - it will help your content to be understood by search engines, screen readers and (perhaps most importantly) your designers. The course then moves on to some of the features that support mobile apps. This includes media queries for responsive design, of course. But perhaps a little less well-known is the support for geolocation and off-line working. The course concludes with the latest CSS3 support for responsive design. This includes some amazing stuff for responsive column layouts, and flexbox for responsive arrangements of elements within a container. It saves you so much time and hassle and quickly gets you a cool design that will amaze your users. So, time to throw away all your tools for native web apps and just build with responsive web standards. Then _everyone_ will be able to see your app, no matter what device they are using so long as it has a modern browser!