no message

css/25.css

@@ -12,6 +12,16 @@ body{
     position: relative;
     /* 100%窗口宽度 */
     width: 100vw;
+    display: flex;
+}
+.main{
+    flex: 1;
+    height: calc(100vh - 43px);
+    position: relative;
+    top: 43px;
+    display: flex;
+    justify-content: center;
+    align-items: center;
 }
 #checkbox{
     /* 隐藏复选框 */

html/25.html

@@ -53,6 +53,9 @@
                 </a>
             </li>
         </ul>
+        <div class="main">
+            我是内容区
+        </div>
     </div>
 </body>