Flick through Cards
You can look through all of your Cards with the [Up] and [Down] arrow keys.
Minimising and Revealing Card Content
Use the [Left] arrow key to minimise/unminimise the Card body. For long cards you can reveal the complete card by pressing the [Right] arrow key.
Junk a card you are focused on using the [Delete] or [FN + Backspace] key.
You can preview any card using [Space]
You can open any card by using [Shift] + [Space], and then return to the previous view using [Cmd / Ctrl] + [Left] arrow keys.