Bootstrap 3: Stretch content

by gergana

HTML

<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css">
<div class="container">
    <div class="row-flex">
      <div class="input-group">
        <div class="hidden">
          <input type="hidden" class="form-control">
          <p class="help-block help-block-error"></p>
        </div>
        <div class="form-group">
          <input type="text" class="form-control">
          <p class="help-block help-block-error"></p>
        </div>
      </div>
      <div class="">
        <button type="submit" class="btn btn-primary">VEEEEEEEEEEEEEERY LONG CONTENT</button>
      </div>
      <div class="">
        <button type="button" class="btn">Очистить</button>
      </div>
    </div>
</div>



<div class="container">
    <div class="row-flex">
      <div class="input-group">
        <div class="hidden">
          <input type="hidden" class="form-control">
          <p class="help-block help-block-error"></p>
        </div>
        <div class="form-group">
          <input type="text" class="form-control">
          <p class="help-block help-block-error"></p>
        </div>
      </div>
      <div class="">
        <button type="submit" class="btn btn-primary">SHORT CONTENT</button>
      </div>
      <div class="">
        <button type="button" class="btn">Очистить</button>
      </div>
    </div>
</div>

CSS

body {
    margin: 10px;
}

.row-flex {
  display: flex;
  justify-content: space-between;
}

.input-group {
  flex: 1;
  margin-right: 10px;
}