Dar estilos a los placeholders con css
input::-webkit-input-placeholder {
color: black;
}
input:focus::-webkit-input-placeholder {
color: gray;
}
/* Firefox < 19 */
input:-moz-placeholder {
color: black;
}
input:focus:-moz-placeholder {
color: gray;
}
/* Firefox > 19 */
input::-moz-placeholder {
color: black;
opacity: 1;
}
input:focus::-moz-placeholder {
color: gray;
}
/* Internet Explorer 10 */
input:-ms-input-placeholder {
color: black;
}
input:focus:-ms-input-placeholder {
color: gray;
}