Color symbolism in HK would be largely Chinese color symbolism but there are big cultural differences between Guangdong and northern China.
Here is the color symbolism I have learned. Others may wish to fill out the list:
Red - good luck, stock market going up, money
white - the soul of the deceased on voyage to the afterlife.
yellow - the color of Chinese royal house.
black ?
purple ?
blue ?
orange ?
green ?
These colors can be important for clothing, or for the type of stone one wears in a pendant or ring.