i think the color code 00ff00 is looks like a bright green color

Actually, the color code 00ff00 in hexadecimal represents a bright green color, and you are correct that it is perceived as bright by the human eye. This RGB color code directly translates into the following values for red, green, and blue:

• Red: 00 (0)
• Green: ff (255)
• Blue: 00 (0)

Since the green channel is at its maximum value (255) while the red and blue channels are both at 0, this results in a vivid and bright shade of green. The high intensity of the green light combined with the absence of red and blue wavelengths is why this particular green appears very bright.