如何在bootstrap中自定义两个文本输入之间的间距

<div class="form-group">
  <label for="input1">输入1</label>
  <input type="text" class="form-control" id="input1" style="margin-right: 10px;">
  <label for="input2">输入2</label>
  <input type="text" class="form-control" id="input2">
</div>

<style>
  .input-spacing {
    margin-right: 10px;
  }
</style>

<div class="form-group">
  <label for="input1">输入1</label>
  <input type="text" class="form-control input-spacing" id="input1">
  <label for="input2">输入2</label>
  <input type="text" class="form-control" id="input2">
</div>

<div class="form-group">
  <div class="col-md-6">
    <label for="input1">输入1</label>
    <input type="text" class="form-control" id="input1">
  </div>
  <div class="col-md-6">
    <label for="input2">输入2</label>
    <input type="text" class="form-control" id="input2">
  </div>
</div>