如何在不影响导航栏高度的情况下在Bootstrap 4导航栏导航项目中创建居中和下方的小文本对齐图标？

.nav-item-icon {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.nav-item-icon span {
  margin-top: 5px; /* 调整文本与图标的间距 */
}

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Logo</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarNav">
    <ul class="navbar-nav">
      <li class="nav-item">
        <a class="nav-link" href="#">
          <span class="nav-item-icon">
            <i class="fa fa-home"></i>
            <span>首页</span>
          </span>
        </a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">
          <span class="nav-item-icon">
            <i class="fa fa-user"></i>
            <span>个人中心</span>
          </span>
        </a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">
          <span class="nav-item-icon">
            <i class="fa fa-envelope"></i>
            <span>消息</span>
          </span>
        </a>
      </li>
    </ul>
  </div>
</nav>