mixin_example.scss

/* This generates no CSS output by itself */

@mixin zeroed {
    margin: 0;
    padding: 0;
    list-style: none;

    li {
        margin: 0;
        padding: 0;
    }
}

/* These two will output as though you'd 
manually written the above into them */

ul.some-vertical-list {
    @include zeroed;

    font-size:18px;
    font-weight:bold;
}

ul.some-horizontal-list {
    @include zeroed;

    font-size:10px;
    display: inline;

    li {
        display: inline;
    }
}