Update index.html

index.html

@@ -174,8 +174,10 @@
     </div>
 
     <div id="image-modal">
-        <img id="modal-image" alt="全尺寸图片">
-        <button id="close-modal">×</button>
+        <button id="image-close" class="modal-close" aria-label="关闭">&times;</button>
+        <button id="image-prev" class="modal-nav" aria-label="上一张">&lsaquo;</button>
+        < img id="modal-image" alt="全尺寸图片">
+        <button id="image-next" class="modal-nav" aria-label="下一张">&rsaquo;</button>
     </div>
 
     <script src="script.js"></script>