Articulate Storyline 2 and most other development tools output in HTML5, which means the content will shrink to the size of the screen it’s being viewed on. If we’re building a course for PC/MAC, the course will still function smoothly on a tablet, since the size of a tablet screen isn’t much smaller than the screen of a PC/MAC. But, when you view that course on a smartphone, the size of a smartphone screen is so much smaller than a PC/MAC, that the functionality of the course will become clunky. Shrink-to-fit only works to a point.