修正

frontend/opening_balance.html

@@ -39,10 +39,9 @@
     <br />
 
     <button onclick="saveOpeningBalances()">保存</button>
-    <a href="index.html">← 戻る</a>
+    <button onclick="location.href='trial-balance.html'">← 戻る</button>
 
     <script src="js/api.js"></script>
     <script src="js/opening_balance.js"></script>
   </body>
 </html>
-s