What
The viewport is the user's visible area of a web page.
Why
The viewport varies with the device, and will be smaller on a mobile phone than on a computer screen. Essentially resizing the smaller it got.
The viewport offered a quick fix but isn't perfect.
The browser will try and fit the whole page onto your device and if the elements are too big it will not work.
The elements need to resize for smaller devices.
Forest Pathways uses three break points (ie for example the font size) has three different settings for small, medium and large. The viewport on mobile in the browser will then detect small/mobile and use the font that is set for small mobile.
With the viewport meta tag