Html 无法使用角带将svg徽标添加到导航栏

基于，我创建了一个简单的导航栏，上面有图像，而不是“品牌”的文本。但是，我的.svg图像不可见。为什么?

            <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
                    <ul class="nav navbar-nav">
                            <li>
                                    <button type="button" class="btn btn-lg btn-primary" data-animation="am-flip-x" bs-dropdown="networks_dropdown">
                                            Networks
                                    </button>
                            </li>
                            <li class="active">
                                    <a href="#">Workplace</a>
                            </li>
                            <li>
                                    <a href="#">Generate</a>
                            </li>
                            <li>
                                    <a href="#">Export</a>
                            </li>
                            <li>
                                    <a href="#">Training</a>
                            </li>
                            <li>
                                    <a href="#">Settings</a>
                            </li>
                    </ul>
                    <ul class="nav navbar-nav navbar-right">
                            <li><a href="#">Logout</a></li>
                    </ul>
            </div>
    </div>

SSCCE：

            <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
                    <ul class="nav navbar-nav">
                            <li>
                                    <button type="button" class="btn btn-lg btn-primary" data-animation="am-flip-x" bs-dropdown="networks_dropdown">
                                            Networks
                                    </button>
                            </li>
                            <li class="active">
                                    <a href="#">Workplace</a>
                            </li>
                            <li>
                                    <a href="#">Generate</a>
                            </li>
                            <li>
                                    <a href="#">Export</a>
                            </li>
                            <li>
                                    <a href="#">Training</a>
                            </li>
                            <li>
                                    <a href="#">Settings</a>
                            </li>
                    </ul>
                    <ul class="nav navbar-nav navbar-right">
                            <li><a href="#">Logout</a></li>
                    </ul>
            </div>
    </div>

来自

---

它在那里，但父元素似乎没有任何宽度。如果添加，则会显示徽标

            <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
                    <ul class="nav navbar-nav">
                            <li>
                                    <button type="button" class="btn btn-lg btn-primary" data-animation="am-flip-x" bs-dropdown="networks_dropdown">
                                            Networks
                                    </button>
                            </li>
                            <li class="active">
                                    <a href="#">Workplace</a>
                            </li>
                            <li>
                                    <a href="#">Generate</a>
                            </li>
                            <li>
                                    <a href="#">Export</a>
                            </li>
                            <li>
                                    <a href="#">Training</a>
                            </li>
                            <li>
                                    <a href="#">Settings</a>
                            </li>
                    </ul>
                    <ul class="nav navbar-nav navbar-right">
                            <li><a href="#">Logout</a></li>
                    </ul>
            </div>
    </div>

.navbar-brand {
    float: left;
    height: 50px;
    padding: 15px 15px;
    font-size: 18px;
    line-height: 20px;
    width: 50px; /* see here */
}