Bootstrap 4 调整引导输入元素的帮助文本

我需要调整输入注释后帮助文本的间距工作电话与其描述性文本之间的额外间距：

再培训局：

---

输入和帮助文本之间的空格是由输入组中的类mb-3引起的

.mb-3, .my-3 {
    margin-bottom: 1rem!important;
}

如果删除该类，则边距将消失：

<div class="form-row">

  <div class="form-group col-md-4">
    <label for="inputWorkEmail">Work Email</label>
    <input type="email" class="form-control" id="inputWorkEmail" name="contact[work_email]" aria-describedby="emailHelp" placeholder="first.last@company.web" value="<%= @contact[:work_email] %>">
    <small id="emailHelp" class="form-text text-muted">Work email address of the contact.</small>
  </div>

  <div class="form-group col-md-4">
    <label for="inputWorkTelephone">Work Telephone</label>
    <div class="input-group">
      <div class="input-group-prepend">
        <span class="input-group-text" id="basic-addon3"><i class="fas fa-phone"></i></span>
      </div>
      <input type="tel" class="form-control" id="inputWorkTelephone" name="contact[work_telephone]" aria-describedby="telephoneHelp" placeholder="800-555-1212" value="<%= @contact[:work_telephone] %>">
    </div>
    <small id="telephoneHelp" class="form-text text-muted">Work telephone number of the contact.</small>
  </div>
</div>

---

更正的代码在此

上如果要保留该类，只需使用style属性进行修改

<div class="form-row">

  <div class="form-group col-md-4">
    <label for="inputWorkEmail">Work Email</label>
    <input type="email" class="form-control" id="inputWorkEmail" name="contact[work_email]" aria-describedby="emailHelp" placeholder="first.last@company.web" value="<%= @contact[:work_email] %>">
    <small id="emailHelp" class="form-text text-muted">Work email address of the contact.</small>
  </div>

  <div class="form-group col-md-4">
    <label for="inputWorkTelephone">Work Telephone</label>
    <div class="input-group">
      <div class="input-group-prepend">
        <span class="input-group-text" id="basic-addon3"><i class="fas fa-phone"></i></span>
      </div>
      <input type="tel" class="form-control" id="inputWorkTelephone" name="contact[work_telephone]" aria-describedby="telephoneHelp" placeholder="800-555-1212" value="<%= @contact[:work_telephone] %>">
    </div>
    <small id="telephoneHelp" class="form-text text-muted">Work telephone number of the contact.</small>
  </div>
</div>