style: Add elNamespace

feat(component): Add namespace of class

src/components/Footer/src/Footer.vue

@@ -1,6 +1,11 @@
 <script setup lang="ts">
 import { useAppStore } from '@/store/modules/app'
 import { computed } from 'vue'
+import { useDesign } from '@/hooks/web/useDesign'
+
+const { getPrefixCls } = useDesign()
+
+const prefixCls = getPrefixCls('footer')
 
 const appStore = useAppStore()
 
@@ -8,5 +13,10 @@ const title = computed(() => appStore.getTitle)
 </script>
 
 <template>
-  <div class="text-center text-[var(--el-text-color-placeholder)]">Copyright ©2021 {{ title }}</div>
+  <div
+    :class="prefixCls"
+    class="text-center text-[var(--el-text-color-placeholder)] bg-[var(--app-contnet-bg-color)] h-[var(--app-footer-height)] leading-[var(--app-footer-height)]"
+  >
+    Copyright ©2021 {{ title }}
+  </div>
 </template>