Html 如何更改引导4中导航栏的引导汉堡图标？

我在为bootstrap 4更改导航栏中的图标时遇到问题。我目前的html格式如下：

<nav class="navbar fixed-top navbar-expand-md navbar-custom">
  <a class="navbar-brand" href="#">
    <img src="images/logo.svg" width="60px" style="margin-right: 10px;" alt="logo">
    <span class="logo-text logo-text-small">Brand</span>
  </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 active">
        <a class="nav-link" href="#">Features<span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricing</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Contact</a>
      </li>
    </ul>
  </div>
</nav>

---

图像位于

images/hamburger icon.svg

中，我在这里做错了什么？

使用开发工具检查元素。您的

背景图像是应用于元素的最后一幅吗？如果不是，那么您需要增加特定性。这是最后一个，但图像没有显示吗？在“网络”选项卡中，检查浏览器要准确加载的路径，以及该路径下是否有可用的图像。
Dear please use this css it will work:


 .navbar-light .navbar-toggler-icon {
       background-image: url("images/hamburger-icon.svg");
       background-size: 100%;
       background-position: center center;
       width: 30px;
       height: 30px;
       display: flex;
    }

    .navbar-inverse .navbar-toggler-icon {
       background-image: url("images/hamburger-icon.svg");
       background-size: 100%;
       background-position: center center;
       width: 30px;
       height: 30px;
       display: flex;

    }

    .custom-toggler .navbar-toggler-icon {
       background-image: url("images/hamburger-icon.svg");
       background-size: 100%;
       background-position: center center;
       width: 30px;
       height: 30px;
       display: flex;
     }

Dear please use this css it will work:


 .navbar-light .navbar-toggler-icon {
       background-image: url("images/hamburger-icon.svg");
       background-size: 100%;
       background-position: center center;
       width: 30px;
       height: 30px;
       display: flex;
    }

    .navbar-inverse .navbar-toggler-icon {
       background-image: url("images/hamburger-icon.svg");
       background-size: 100%;
       background-position: center center;
       width: 30px;
       height: 30px;
       display: flex;

    }

    .custom-toggler .navbar-toggler-icon {
       background-image: url("images/hamburger-icon.svg");
       background-size: 100%;
       background-position: center center;
       width: 30px;
       height: 30px;
       display: flex;
     }