Html 引导最小固定宽度内柔体

我试图使一个类似于holidaypiratescom搜索字段的引导smth搜索栏

我需要有最小宽度的第一个和最后一个按钮，同时让3个表单字段的灵活性。如果我直接用cssmin width设置宽度，当我缩小屏幕时，按钮元素会粘在卡的外面。我不知道怎么做，有什么建议吗

<div class="card">
<div class="search-box d-md-inline-flex">

<!-- col1 -->
<div class="card border-0">
  <input class="btn btn-primary" type="text" name="" value="All categories">
</div>
<!-- col2 -->
<div class="card border-0">
    <input class="form-control mr-2" type="text" name="departure" placeholder="Departure">
</div>
<!-- col3 -->
<div class="card border-0">
    <input class="form-control mr-2" type="text" name="destination" placeholder="Destination">
</div>
<!-- col4 -->
<div class="card border-0">
    <input class="form-control mr-2" type="text" name="type" placeholder="Travel Period">
</div>
<!-- Submit -->
<div class="card border-0">
    <input class="btn btn-primary" type="submit" name="" value="go">
</div>

</div><!--/search-box -->
</div> <!-- /card -->

使用容器类包装内容。对于响应性使用，lg、md、sm适用于该类

<div class="card container">
    <div class="container">
      <div class="search-box d-md-inline-flex">

      <!-- col1 -->
      <div class="card border-0 p-3">
        <input class="btn btn-primary" type="text" name="" value="All categories">
      </div>
      <!-- col2 -->
      <div class="card border-0 p-3">
          <input class="form-control mr-2" type="text" name="departure" placeholder="Departure">
      </div>
      <!-- col3 -->
      <div class="card border-0 p-3">
          <input class="form-control mr-2" type="text" name="destination" placeholder="Destination">
      </div>
      <!-- col4 -->
      <div class="card border-0 p-3">
          <input class="form-control mr-2" type="text" name="type" placeholder="Travel Period">
      </div>
      <!-- Submit -->
      <div class="card border-0 p-3">
          <input class="btn btn-primary" type="submit" name="" value="go">
      </div>

      </div><!--/search-box -->
    </div>
  </div>