CSSPrefixer

A tool that rewrites your CSS files, adding vendor-prefixed versions of (popular) CSS3 rules. It also can combine and minify your stylesheets. Keep your styles clean!

It supports many CSS3 stuff including Flexbox, but not Gradients yet.

For example, this

#wrapper {
    border-radius: 1em;
    transform: rotate(45deg)
}

becomes this:

#wrapper {
    border-radius: 1em;
    transform: rotate(45deg);
    -webkit-border-radius: 1em;
    -moz-border-radius: 1em;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -o-transform: rotate(45deg)
}

Requires cssutils.