<div class="demo_grid">
    <div class="row">
        <div class="col-md-12">
            <div class="col-wrapper">.col-md-12</div>
        </div>
    </div>
    <div class="row">
        <div class="col-md-6">
            <div class="col-wrapper">
                .col-md-6
                <div class="row">
                    <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
                    <div class="col-sm-2"><div class="col-wrapper">.col-sm-2</div></div>
                    <div class="col-sm-7"><div class="col-wrapper">.col-sm-7</div></div>
                </div>
            </div>
        </div>
        <div class="col-md-6">
            <div class="col-wrapper">
                .col-md-6
                <div class="row">
                    <div class="col-sm-6"><div class="col-wrapper">.col-sm-6</div></div>
                    <div class="col-sm-6"><div class="col-wrapper">.col-sm-6</div></div>
                </div>
            </div>
        </div>
    </div>
    <div class="row">
        <div class="col-md-4"><div class="col-wrapper">.col-md-6</div></div>
        <div class="col-md-3"><div class="col-wrapper">.col-md-3</div></div>
        <div class="col-md-5"><div class="col-wrapper">.col-md-5</div></div>
    </div>
    <div class="row">
        <div class="col-md-4"><div class="col-wrapper">.col-md-4</div></div>
        <div class="col-md-4"><div class="col-wrapper">.col-md-4</div></div>
        <div class="col-md-4"><div class="col-wrapper">.col-md-4</div></div>
    </div>
    <div class="row">
        <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
        <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
        <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
        <div class="col-sm-3"><div class="col-wrapper">.col-sm-30</div></div>
    </div>
    <div class="row">
        <div class="col-lg-8"><div class="col-wrapper">.col-lg-8</div></div>
        <div class="col-lg-4"><div class="col-wrapper">.col-lg-4</div></div>
    </div>
    <div class="row">
        <div class="col-lg-6">
            <div class="col-wrapper">
                .col-lg-6
                <div class="row">
                    <div class="col-md-10">
                        <div class="col-wrapper">
                            .col-md-10
                            <div class="row">
                                <div class="col-sm-6"><div class="col-wrapper">.col-sm-6</div></div>
                                <div class="col-sm-6"><div class="col-wrapper">.col-sm-6</div></div>
                            </div>
                        </div>
                    </div>
                    <div class="col-md-2">
                        <div class="col-wrapper">
                            .col-md-2
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <div class="col-lg-6">
            <div class="col-wrapper">
                .col-lg-6
                <div class="row">
                    <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
                    <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
                    <div class="col-sm-3"><div class="col-wrapper">.col-sm-3</div></div>
                    <div class="col-sm-3"><div class="col-wrapper">.col-sm-30</div></div>
                </div>
            </div>
        </div>
    </div>
</div>