Upload: add missing doc styles (#2996)

examples/docs/en-US/upload.md

@@ -128,6 +128,33 @@ Use `before-upload` hook to limit the upload file format and size.
   <img v-if="imageUrl" :src="imageUrl" class="avatar">
   <i v-else class="el-icon-plus avatar-uploader-icon"></i>
 </el-upload>
+
+<style>
+  .avatar-uploader .el-upload {
+    border: 1px dashed #d9d9d9;
+    border-radius: 6px;
+    cursor: pointer;
+    position: relative;
+    overflow: hidden;
+  }
+  .avatar-uploader .el-upload:hover {
+    border-color: #20a0ff;
+  }
+  .avatar-uploader-icon {
+    font-size: 28px;
+    color: #8c939d;
+    width: 178px;
+    height: 178px;
+    line-height: 178px;
+    text-align: center;
+  }
+  .avatar {
+    width: 178px;
+    height: 178px;
+    display: block;
+  }
+</style>
+
 <script>
   export default {
     data() {

examples/docs/zh-CN/upload.md

@@ -169,6 +169,33 @@
   <img v-if="imageUrl" :src="imageUrl" class="avatar">
   <i v-else class="el-icon-plus avatar-uploader-icon"></i>
 </el-upload>
+
+<style>
+  .avatar-uploader .el-upload {
+    border: 1px dashed #d9d9d9;
+    border-radius: 6px;
+    cursor: pointer;
+    position: relative;
+    overflow: hidden;
+  }
+  .avatar-uploader .el-upload:hover {
+    border-color: #20a0ff;
+  }
+  .avatar-uploader-icon {
+    font-size: 28px;
+    color: #8c939d;
+    width: 178px;
+    height: 178px;
+    line-height: 178px;
+    text-align: center;
+  }
+  .avatar {
+    width: 178px;
+    height: 178px;
+    display: block;
+  }
+</style>
+
 <script>
   export default {
     data() {