The headlights and the radio take a lot less power than the starter, so the radio can operate and the lights work but the starter won’t turn the engine over. Putting gasoline in the tank when the battery is dead won’t have any effect. You may be able to jump the battery from another car. Just be certain that you know the procedure–positive of the car with the good battery to the positive terminal in your Civic, then connect the negative terminal of the good battery to some place on the engine block away from the battery. If the car starts, disconnect in the reverse order of above.