How to compile css style rules with component/block etc.?

[lockedscope]

We could use bem-xjst to create html but how do we generate style rules automatically?
So, we could easily fill those styles. Bem project stub contains components but i could not find a way to create my own css automatically.

https://github.com/bem/project-stub

:block(checkbox):mod(theme islands) {
    position: relative; /* fix #1538 */

    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;

    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);

    &:hover {
        cursor: normalx;
    }

    :block(checkbox):elem(control) {
        position: absolute;
        z-index: -1;

        margin: 0;

}

[lockedscope]

This issue could be deleted