<form action="" method="post">
    <div class="form_control">
        <button type="button" class="btn btn-green">btn btn-green</button>
        <button type="button" class="btn btn-blue">btn btn-blue</button>
        <button type="button" class="btn btn-red">btn btn-red</button>
        <button type="button" class="btn btn-lightgray">btn btn-lightgray</button>
        <button type="button" class="btn btn-darkgray">btn btn-darkgray</button>
    </div>
    <div class="form_control">
        <button type="button" class="btn btn-green btn-xs">btn btn-green btn-xs</button>
        <button type="button" class="btn btn-blue btn-s">btn btn-blue  btn-s</button>
        <button type="button" class="btn btn-red btn-m">btn btn-red btn-m</button>
        <button type="button" class="btn btn-lightgray btn-l">btn btn-lightgray btn-l</button>
        <button type="button" class="btn btn-darkgray btn-xl">btn btn-darkgray btn-xl</button>
    </div>
</form>