Instead of using a character here I would just set a `height` and `width` value. Then you can style each using `background-color` below.

e.g.

    ul {
        list-style: none;
        li {
            position: relative;
            font-size: 12px;
            text-indent: 12px;
        }
    }
    li:before {
        position: absolute;
        top: 6px;
        left: 0;
        content: '';
        width: 8px;
        height: 8px;
    }