uiKit: Responsive media queries breakpoints.

Useful media queries breakpoint when using uiKit(3) framework.

Class	Description
`[email protected]`	Only affects device widths of 640px and larger.
`[email protected]`	Only affects device widths of 960px and larger.
`[email protected]`	Only affects device widths of 1200px and larger.
`[email protected]`	Only affects device widths of 1600px and larger.