Provide zoom in/out functionality

[darekkay]

In the past I have evaluated a fluid typography design, i.e., the possibility for widgets to scale their font size based on the widget size. See my explanation for why I have abandoned this idea.

Instead, constant font sizes are used for all widgets and all breakpoints. While the user can use native browser zoom functionality, zoom in/out buttons in the header may improve the UX (especially for less tech-savvy people).

It is to be checked whether the header itself should be zoomed as well, or just the content.

One possible solution is using the CSS transform: scale(x) function.