diff --git a/package.json b/package.json
index d49eeed..ae0440c 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,7 @@
     "element-ui": "^2.0.9",
     "font-awesome": "^4.7.0",
     "highlight.js": "^9.12.0",
-    "iview": "^2.8.0",
+    "iview": "^2.13.0",
     "moment": "^2.20.1",
     "papaparse": "^4.3.6",
     "raven-js": "^3.21.0",
diff --git a/src/pages/oj/components/NavBar.vue b/src/pages/oj/components/NavBar.vue
index a5ba918..3fe04dd 100644
--- a/src/pages/oj/components/NavBar.vue
+++ b/src/pages/oj/components/NavBar.vue
@@ -129,8 +129,8 @@
 
 <style lang="less" scoped>
   #header {
+    min-width: 1100px;
     position: fixed;
-    overflow: hidden;
     top: 0;
     left: 0;
     height: 60px;
@@ -151,10 +151,10 @@
     }
 
     .drop-menu {
-      float: right;
-      margin-right: 40px;
+      position: absolute;
+      right: 10px;
       &-title {
-        font-size: 18px;
+        font-size: 16px;
       }
     }
     .btn-menu {
diff --git a/src/pages/oj/components/mixins/problem.js b/src/pages/oj/components/mixins/problem.js
index d973960..f0e4fc3 100644
--- a/src/pages/oj/components/mixins/problem.js
+++ b/src/pages/oj/components/mixins/problem.js
@@ -23,7 +23,7 @@ export default {
         return
       }
       tableColumns.splice(0, 0, {
-        width: '60',
+        width: 60,
         title: ' ',
         render: (h, params) => {
           let status = params.row.my_status
diff --git a/src/pages/oj/views/contest/ContestList.vue b/src/pages/oj/views/contest/ContestList.vue
index d52359b..ae3dc54 100644
--- a/src/pages/oj/views/contest/ContestList.vue
+++ b/src/pages/oj/views/contest/ContestList.vue
@@ -38,7 +38,7 @@
       </div>
       <p id="no-contest" v-if="contests.length == 0">No contest</p>
       <ol id="contest-list">
-        <li v-for="contest in contests">
+        <li v-for="contest in contests" :key="contest.title">
           <Row type="flex" justify="space-between" align="middle">
             <img class="trophy" src="../../../../assets/Cup.png"/>
             <Col :span="18" class="contest-main">
@@ -197,6 +197,7 @@
       > li {
         padding: 20px;
         border-bottom: 1px solid rgba(187, 187, 187, 0.5);
+        list-style: none;
 
         .trophy {
           height: 40px;
diff --git a/src/pages/oj/views/general/Announcements.vue b/src/pages/oj/views/general/Announcements.vue
index 5e46254..76a8660 100644
--- a/src/pages/oj/views/general/Announcements.vue
+++ b/src/pages/oj/views/general/Announcements.vue
@@ -14,7 +14,7 @@
       </div>
       <template v-if="listVisible">
         <ul class="announcements-container" key="list">
-          <li v-for="announcement, index in announcements">
+          <li v-for="announcement in announcements" :key="announcement.title">
             <div class="flex-container">
               <div class="title"><a class="entry" @click="goAnnouncement(announcement)">
                 {{announcement.title}}</a></div>
@@ -126,6 +126,7 @@
     margin-bottom: 10px;
     li {
       padding-top: 15px;
+      list-style: none;
       padding-bottom: 15px;
       margin-left: 20px;
       font-size: 16px;
diff --git a/src/pages/oj/views/problem/ProblemList.vue b/src/pages/oj/views/problem/ProblemList.vue
index e36c27b..4c23afa 100644
--- a/src/pages/oj/views/problem/ProblemList.vue
+++ b/src/pages/oj/views/problem/ProblemList.vue
@@ -91,6 +91,7 @@
           {
             title: '#',
             key: '_id',
+            width: 80,
             render: (h, params) => {
               return h('Button', {
                 props: {
@@ -110,7 +111,6 @@
           },
           {
             title: 'Title',
-            width: '35%',
             render: (h, params) => {
               return h('Button', {
                 props: {
@@ -236,7 +236,7 @@
             {
               title: 'Tags',
               align: 'center',
-              width: '200px',
+              width: 200,
               render: (h, params) => {
                 let tags = []
                 params.row.tags.forEach(tag => {