A mobile device comprises a display panel configured to display a plurality of graphic user interfaces including one or more first type graphic user interfaces and/or one or more second type graphic user interfaces; one or more sensors configured to detect a position of a user; and one or more processors configured to: calculate a relative inclination of the display panel with respect to the position of the user based on the position of the user detected by the sensor, and change sizes of the first type graphic user interfaces among the plurality of graphic user interfaces based on the relative inclination of the display panel. The first type graphic user interfaces are pre-designated among the plurality of graphic user interfaces and stored in memory, and the processors are configured to magnify the sizes of the first type graphic user interfaces according to the relative inclination of the display panel.