feat: header阴影

src/components/Header.vue

@@ -491,7 +491,7 @@ export default {
 </script>
 <style scoped>
 .header {
-    position: relative;
+  position: fixed;
     box-sizing: border-box;
     width: 100%;
     height: 70px;
@@ -499,6 +499,8 @@ export default {
     color: #000000;
     background-color: #fff;
     font-weight: bold;
+    box-shadow: 0 2px 12px 0 rgba(0, 0, 0, 0.1);
+    z-index: 1000;
 }
 .collapse-btn {
     float: left;
@@ -506,7 +508,6 @@ export default {
     cursor: pointer;
     line-height: 70px;
     background-color: #ffffff;
-
 }
 
 .user-avator img {