Something like this:

.pages {
    background-size: cover;
}
#slide-01 {
    background: url(lalala.png) no-repeat;
    background-size: cover;
}

output:

.pages, #slide-01{
    background-size:cover
}

#slide-01{
    background:url(lalala.png) no-repeat
}

background-size is overriden with default value

Bye, csso

@silentroach What are you using instead? This project looks quite dead.

@magnars that's true :(
suggest to switch to https://github.com/jakubpawlowicz/clean-css

Very sad, csso idea is great

@silentroach yeah, but nowadays structural optimisations are quite common idea

new hope!

It's similar to #143, but examples could be useful for tests.

Current output for first example:

.support-question .closed,.support-question .opened {
    background: url('/s/a/i/ic/util.gif') no-repeat top right;
    white-space: nowrap;
    padding-right: 15px
}

.support-question .closed {
    background-position: right -65px
}

.support-question .opened {
    background-position: right -450px
}

It's correct. But because of good enough declaration positions.
Second example is still fail...

What about second example, it's even possible without context?
How csso can know which block is encapsulates other?

@ArturAralin what context your talking about? All we need is knowledge about shorthand properties and others (I call it property family) to make proper merge. If you're interesting in problem here is the branch where I started work on this problem (unfinished yet).