Best approach to support light-dark function

/* 1 */
::placeholder {
    color: #757575;
    color: light-dark(hsl(0deg 0% 46%), hsl(0deg 0% 65%));
}

/* 2 */
::placeholder {
    color: #757575;
}
@supports (color: light-dark(black, white)) {
    ::placeholder {
        color: light-dark(hsl(0deg 0% 46%), hsl(0deg 0% 65%));
    }
}