style: change background color in dark mode (#242)

Co-authored-by: lior_ren <lior_ren@huatek.com>

Author: Liorocky

index.html

@@ -17,6 +17,11 @@
     .markdown-section code {
       font-weight: 400;
     }
+
+    /* dark mode 全局文章图片背景色 */
+    article img {
+      background-color: #42b983;
+    }
   </style>
 </head>