update: update

src/views/activity/component/CategoryDialog.vue

 <template>
-  <el-dialog custom-class="category-dialog" :visible.sync=" dialogVisible" :rules="rules"
+  <el-dialog custom-class="category-dialog" :visible.sync=" dialogVisible" :rules="rules" class="category-dialog-wrap"
     width="600px" :close-on-click-modal="false" :close-on-press-escape="false">
     <div v-loading="loading">
       <el-row type="flex" justify="space-between">
@@ -223,7 +223,13 @@ export default {
 }
 </style>
 <style lang="less">
+.category-dialog-wrap{
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
 .category-dialog {
+  margin: 0 !important;
   padding: 0 4px 4px;
   max-height: 700px;
   .el-dialog__header {