Autoprefixer writes new styles for each prefixed property instead of grouping them

[citedev]

When I write:

input::placeholder, textarea::placeholder {
    font-size: 14px;
    opacity: 0.7;

I expect to see something like that:

input::-webkit-input-placeholder, textarea::-webkit-input-placeholder,
input::-moz-placeholder, textarea::-moz-placeholder,
input:-ms-input-placeholder, textarea:-ms-input-placeholder,
input::-ms-input-placeholder, textarea::-ms-input-placeholder,
input::placeholder, textarea::placeholder {
    font-size: 14px;
    opacity: 0.7;

But it does that:

input::-webkit-input-placeholder, textarea::-webkit-input-placeholder {
    font-size: 14px;
    opacity: 0.7;
}

input::-moz-placeholder, textarea::-moz-placeholder {
    font-size: 14px;
    opacity: 0.7;
}

input:-ms-input-placeholder, textarea:-ms-input-placeholder {
    font-size: 14px;
    opacity: 0.7;
}

input::-ms-input-placeholder, textarea::-ms-input-placeholder {
    font-size: 14px;
    opacity: 0.7;
}

input::placeholder, textarea::placeholder {
    font-size: 14px;
    opacity: 0.7;

Any way to fix ?

[ai]

Autoprefixer does it for reason.

Browser will ignore the whole group of any selector is invalid (for instance, because of vendor prefix).

[citedev]

Autoprefixer does it for reason.

Browser will ignore the whole group of any selector is invalid (for instance, because of vendor prefix).

Thanks for the lightning-fast response, good explanation.