Fieldset and legend

<fieldset class="mbm">
<legend>
  Are you real
</legend>
<div>
  <label class="form__radio mrm"><input type="radio" name="real" checked />Yes</label>
  <label class="form__radio mrm"><input type="radio" name="real" />No</label>
  <label class="form__radio"><input type="radio" name="real" />Maybe</label>
</div>
</fieldset>

<fieldset>
<legend>
  Container size
</legend>
<div class="flex">
  <label class="form__label mrs">
    Height
    <input class="form__control" />
  </label>
  <label class="form__label mrs">
    Width
    <input class="form__control" />
  </label>
  <label class="form__label">
    Length
    <input class="form__control" />
  </label>
</div>
</fieldset>