Splitting attributes from CSS rules

I want to combine

.alpha {
    border-top: solid 1px #990000 ;
}
.beta {
    border-bottom: solid 5px #990000;
}

into something like

.alpha, .beta {
    border: #990000 ;
}
.alpha {
    border-top: solid 1px;
}
.beta {
    border-bottom: solid 5px;
}

it would make it much easier to easier to change colours programmatically. Is this possible? I should not that I've tried the above开发者_运维知识库 and it doesn't seem to work in Firefox. Only the last rules (i.e. .alpha and .beta) are applied, while the combined is ignored.

Thanks

---

The CSS in your example won't work.

You could use...

.alpha, .beta {
    border-color: #900;
    border-style: solid;
    border-width: 0;
}

.alpha {
    border-top-width: 1px;
}

.beta {
    border-bottom-width: 5px;
}

jsFiddle.