问题 I made a "down arrow" in illustrator and saved it as a png with a transparent background. When I put it into my webpage as an img, it shows up in the original color, which is okay. I'm trying to do img:hover{color:red;} and it doesn't work. Does anyone know how to make it work? Thanks 回答1: If you target modern browsers, you may use CSS filters. The hue-rotate filter is suitable for changing colors: filter: hue-rotate(180deg); -webkit-filter: hue-rotate(180deg); The exact amount of degrees