<div id="app">
            <!-- 卡片区域 -->
            <div class="card">
                <div class="card-header">添加品牌</div>
                <div class="card-body">
                    <!-- 添加品牌的表单区域 -->
                    <!-- form 表单元素有 submit 事件 -->
                    <form @submit.prevent="add">
                        <div class="form-row align-items-center">
                            <div class="col-auto">
                                <div class="input-group mb-2">
                                    <div class="input-group-prepend">
                                        <div class="input-group-text">
                                            品牌名称
                                        </div>
                                    </div>
                                    <input
                                        type="text"
                                        class="form-control"
                                        placeholder="请输入品牌名称"
                                        v-model.trim="brand"
                                    />
                                </div>
                            </div>
                            <div class="col-auto">
                                <button
                                    type="submit"
                                    class="btn btn-primary mb-2"
                                >
                                    添加
                                </button>
                            </div>
                        </div>
                    </form>
                </div>
            </div>