Neon ( 霓虹 ) is to Hong Kong as red phone booths are to London and fog is to San Francisco. When night falls , red and blue and other colors 26 a hazy (雾蒙蒙的 ) glow over a city lit up by tens of thousands of neon signs. But many of them are going dark, 27 by more practical , but less romantic, LEDs ( 发光二极管 ). Changing building codes, evolving tastes, and the high cost of maintaining those wonderful old signs have businesses embracing LEDs, which are energy 28 , but still carry great cost . " To me