style:增加左侧导航及头部导航栏

src/components/BreadCrumb.vue

@@ -0,0 +1,36 @@
+<template>
+  <div class="breadcrumb">
+    <div style="margin-left: 21px">
+      <el-breadcrumb separator="/">
+        <el-breadcrumb-item :to="{ path: '/' }">homepage</el-breadcrumb-item>
+        <el-breadcrumb-item
+          ><a href="/">promotion management</a></el-breadcrumb-item
+        >
+        <el-breadcrumb-item>promotion list</el-breadcrumb-item>
+        <el-breadcrumb-item>promotion detail</el-breadcrumb-item>
+      </el-breadcrumb>
+    </div>
+  </div>
+</template>
+<script>
+import { reactive, toRefs } from "vue";
+export default {
+  name: "BreadCrumb",
+  setup() {
+    const state = reactive({});
+    return {
+      ...toRefs(state),
+    };
+  },
+};
+</script>
+<style scoped lang="scss">
+.breadcrumb {
+  width: 100%;
+  height: 60px;
+  display: flex;
+  align-items: center;
+
+  // background-color: rgba(255, 255, 255, 0.5);
+}
+</style>