A method of operating a mobile computing device, the method comprising: concurrently running, on the mobile computing device, multiple applications each representable on a display screen of the mobile computing device by a corresponding card containing a user interface for the corresponding application; placing a first application of the multiple applications into a hibernation state, wherein the corresponding card of the first application comprises a static snapshot of the user interface for the first application; toggling, in response to a user input, operation of the mobile computing device from a full-screen mode to a card mode, wherein while operating in the card mode, the method further comprises: displaying, on the display screen, the cards in a linear arrangement along an axis of the display screen; moving, in response to a directional touch input along the axis of the display screen, the cards across the display screen in the same direction as the directional touch input; and detecting a tap input on the corresponding card of the first application displayed on the display screen; toggling, in response to the tap input on the corresponding card of the first application, operation of the mobile computing device from the card mode to the full-screen mode; and reviving the first application in response to the tap input on the corresponding card of the first application. concurrently running, on the mobile computing device, multiple applications each representable on a display screen of the mobile computing device by a corresponding card containing a user interface for the corresponding application; placing a first application of the multiple applications into a hibernation state, wherein the corresponding card of the first application comprises a static snapshot of the user interface for the first application; toggling, in response to a user input, operation of the mobile computing device from a full-screen mode to a card mode, wherein while operating in the card mode, the method further comprises: displaying, on the display screen, the cards in a linear arrangement along an axis of the display screen; moving, in response to a directional touch input along the axis of the display screen, the cards across the display screen in the same direction as the directional touch input; and detecting a tap input on the corresponding card of the first application displayed on the display screen; toggling, in response to the tap input on the corresponding card of the first application, operation of the mobile computing device from the card mode to the full-screen mode; and reviving the first application in response to the tap input on the corresponding card of the first application. displaying, on the display screen, the cards in a linear arrangement along an axis of the display screen; moving, in response to a directional touch input along the axis of the display screen, the cards across the display screen in the same direction as the directional touch input; and detecting a tap input on the corresponding card of the first application displayed on the display screen; toggling, in response to the tap input on the corresponding card of the first application, operation of the mobile computing device from the card mode to the full-screen mode; and reviving the first application in response to the tap input on the corresponding card of the first application.