Change the color of Gravity Forms placeholder text

For some reason, changing the “color” of the input text wasn't changing the color of the placeholder text. I came across this code that worked courtesy of Well Made Website:

/* gform placeholders*/
::-webkit-input-placeholder { color:#FFF; }
:-moz-placeholder { opacity: 1; color:#FFF; } /* Firefox 18- */
::-moz-placeholder { opacity: 1; color:#FFF; } /* firefox 19+ */
:-ms-input-placeholder { color:#FFF; } /* ie */
input:-moz-placeholder { color:#FFF; }