修正

backend/app/main.py

@@ -2,9 +2,11 @@ from dotenv import load_dotenv
 load_dotenv()
 
 from fastapi import FastAPI, Request
-from fastapi.responses import JSONResponse, RedirectResponse
+from fastapi.responses import JSONResponse, RedirectResponse, Response
 from pydantic import ValidationError
 from fastapi.middleware.cors import CORSMiddleware
+from starlette.datastructures import MutableHeaders
+from starlette.types import ASGIApp, Receive, Scope, Send
 
 # FastAPI アプリケーション作成
 app = FastAPI(
@@ -12,13 +14,37 @@ app = FastAPI(
 )
 
 
+class SecurityHeadersMiddleware:
+    """キャッシュ禁止・セキュリティヘッダーを全レスポンスに付与（ASGIネイティブ実装）”"""
+    def __init__(self, app: ASGIApp) -> None:
+        self.app = app
+
+    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+        if scope["type"] != "http":
+            await self.app(scope, receive, send)
+            return
+
+        async def send_with_headers(message):
+            if message["type"] == "http.response.start":
+                headers = MutableHeaders(scope=message)
+                headers["Cache-Control"] = "no-store, no-cache, must-revalidate, private"
+                headers["Pragma"] = "no-cache"
+                headers["Expires"] = "0"
+                headers["X-Frame-Options"] = "DENY"
+                headers["X-Content-Type-Options"] = "nosniff"
+                headers["X-XSS-Protection"] = "1; mode=block"
+            await send(message)
+
+        await self.app(scope, receive, send_with_headers)
+
+app.add_middleware(SecurityHeadersMiddleware)
 
 app.add_middleware(
     CORSMiddleware,
     allow_origins=["*"],
     allow_credentials=False,
-    allow_methods=["*"],
+    allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
-    allow_headers=["*"],
+    allow_headers=["Content-Type", "Authorization"],
 )
 
 # ─────────────────────────

backend/app/modules/users/router.py

@@ -12,6 +12,12 @@ class LoginRequest(BaseModel):
     password: str
 
 
+class ChangePasswordRequest(BaseModel):
+    username: str
+    current_password: str
+    new_password: str
+
+
 class LoginResponse(BaseModel):
     id: int
     username: str
@@ -66,39 +72,48 @@ async def login(request: LoginRequest):
 
 @router.post("/register")
 async def register(request: LoginRequest):
-    """新規ユーザー登録"""
+    """新規ユーザー登録（無効化済み）"""
-    try:
+    raise HTTPException(status_code=403, detail="新規ユーザー登録は現在受け付けていません")
-        if len(request.password) < 6:
-            raise HTTPException(status_code=400, detail="パスワードは6文字以上である必要があります")
 
+
+@router.post("/change-password")
+async def change_password(request: ChangePasswordRequest):
+    """パスワード変更"""
+    if len(request.new_password) < 8:
+        raise HTTPException(status_code=400, detail="新しいパスワードは8文字以上である必要があります")
+
+    try:
         conn = get_connection()
         cur = conn.cursor()
 
-        # ユーザーが既に存在するか確認
+        cur.execute(
-        cur.execute("SELECT id FROM users WHERE username = %s", (request.username,))
+            "SELECT id, password FROM users WHERE username = %s AND is_active = TRUE",
-        if cur.fetchone():
+            (request.username,)
+        )
+        user = cur.fetchone()
+
+        if not user:
             cur.close()
             conn.close()
-            raise HTTPException(status_code=400, detail="このユーザー名は既に使用されています")
+            raise HTTPException(status_code=401, detail="ユーザーが見つかりません")
 
-        # ユーザーを登録
+        if user["password"] != hash_password(request.current_password):
-        hashed_password = hash_password(request.password)
+            cur.close()
+            conn.close()
+            raise HTTPException(status_code=401, detail="現在のパスワードが正しくありません")
+
+        new_hashed = hash_password(request.new_password)
         cur.execute(
-            "INSERT INTO users (username, password) VALUES (%s, %s) RETURNING id, username",
+            "UPDATE users SET password = %s WHERE username = %s",
-            (request.username, hashed_password)
+            (new_hashed, request.username)
         )
-        new_user = cur.fetchone()
         conn.commit()
         cur.close()
         conn.close()
 
-        return {
+        return {"message": "パスワードを変更しました"}
-            "id": new_user["id"],
-            "username": new_user["username"],
-            "message": "ユーザー登録が完了しました"
-        }
 
     except HTTPException:
         raise
     except Exception as e:
-        raise HTTPException(status_code=500, detail=f"登録処理エラー: {str(e)}")
+        raise HTTPException(status_code=500, detail=f"パスワード変更エラー: {str(e)}")

frontend/accounts.html

@@ -2,9 +2,11 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
     <title>科目マスタ</title>
     <link rel="stylesheet" href="css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
   </head>
   <body>
     <h1>科目マスタ</h1>

frontend/css/mobile.css

@@ -0,0 +1,324 @@
+/* ==================================================================
+   mobile.css — iOS Safari・Android Chrome レスポンシブ対応
+   ブレークポイント: 767px 以下をモバイルとして扱う
+   PC のレイアウトは変更しない (screen media query で完全に隔離)
+   ================================================================== */
+
+/* ── iOS Safari フォントブースト無効化 ── */
+html {
+  -webkit-text-size-adjust: 100%;
+}
+
+@media screen and (max-width: 767px) {
+
+  /* ── body 余白を縮小 ── */
+  body {
+    padding: 12px !important;
+    margin: 8px !important;
+  }
+
+  /* ── h1・h2 フォントサイズ ── */
+  h1 { font-size: 1.35rem !important; }
+  h2 { font-size: 1.1rem  !important; }
+
+  /* ================================================================
+     テーブル: 横スクロール
+     会計・給与テーブルは列数が多く、横スクロールが最適解
+     ================================================================ */
+  table {
+    display: block;
+    overflow-x: auto;
+    -webkit-overflow-scrolling: touch;
+    max-width: 100%;
+  }
+
+  /* テーブルを包む overflow:hidden ラッパーも解放する */
+  .doc-table-wrap {
+    overflow-x: auto !important;
+  }
+
+  /* ================================================================
+     フォーム入力: 16px で iOS の自動ズームを防ぐ
+     ================================================================ */
+  input[type="text"],
+  input[type="date"],
+  input[type="number"],
+  input[type="password"],
+  input[type="email"],
+  input[type="tel"],
+  select,
+  textarea {
+    font-size: 16px !important;
+    max-width: 100%;
+    box-sizing: border-box;
+  }
+
+  /* ================================================================
+     ボタン: タップ領域を 44px 以上に (iOS HIG 推奨)
+     ================================================================ */
+  button,
+  input[type="submit"],
+  input[type="button"],
+  .btn,
+  .upload-btn,
+  .back-link,
+  .logout-btn,
+  .change-pw-btn {
+    min-height: 44px;
+    touch-action: manipulation;
+  }
+
+  /* ================================================================
+     index.html
+     ================================================================ */
+
+  /* 2カラムカードグリッド → 1カラム */
+  .grid {
+    grid-template-columns: 1fr !important;
+  }
+
+  /* ヘッダー: タイトルとユーザー情報を縦積み */
+  header {
+    flex-direction: column !important;
+    align-items: flex-start !important;
+    gap: 10px !important;
+  }
+
+  header h1 {
+    font-size: 18px !important;
+  }
+
+  .user-info {
+    flex-wrap: wrap !important;
+    width: 100% !important;
+    gap: 8px !important;
+    font-size: 13px !important;
+  }
+
+  /* カード内ボタン群: 縦積み・margin-left をリセット */
+  .card p:last-child {
+    display: flex !important;
+    flex-direction: column !important;
+    gap: 8px !important;
+  }
+
+  .btn {
+    margin-left: 0 !important;
+    display: block !important;
+    text-align: center !important;
+    box-sizing: border-box !important;
+  }
+
+  /* パスワード変更モーダル: 画面幅に合わせる */
+  .modal-box {
+    width: 92vw !important;
+    max-width: 92vw !important;
+    padding: 20px !important;
+  }
+
+  /* ================================================================
+     payroll.html (給与システムメニュー)
+     ================================================================ */
+
+  .menu-grid {
+    grid-template-columns: 1fr !important;
+  }
+
+  .menu-card {
+    padding: 20px !important;
+  }
+
+  /* ================================================================
+     journal-entry.html / journal-edit.html (仕訳入力)
+     ================================================================ */
+
+  /* 検索フォーム: 2カラムグリッド → 1カラム */
+  .search-form-grid {
+    grid-template-columns: 1fr !important;
+    gap: 12px !important;
+  }
+
+  .search-form-row,
+  .search-form-row-full {
+    flex-direction: column !important;
+    align-items: flex-start !important;
+    gap: 4px !important;
+  }
+
+  .search-form-row label,
+  .search-form-row-full label {
+    min-width: unset !important;
+    width: 100%;
+  }
+
+  .search-form-row input,
+  .search-form-row select,
+  .search-form-row-full input,
+  .search-form-row-full select {
+    width: 100% !important;
+    box-sizing: border-box !important;
+  }
+
+  /* 検索ボタン群 */
+  .search-buttons {
+    flex-wrap: wrap !important;
+    gap: 6px !important;
+  }
+
+  .search-buttons button {
+    flex: 1 1 auto !important;
+    min-width: 100px !important;
+  }
+
+  /* .row: 日付・摘要・勘定科目などの入力行 */
+  .row {
+    flex-direction: column !important;
+    align-items: flex-start !important;
+    gap: 6px !important;
+    width: 100%;
+  }
+
+  .row label {
+    min-width: unset !important;
+  }
+
+  .row input,
+  .row select {
+    width: 100% !important;
+    box-sizing: border-box !important;
+  }
+
+  /* ================================================================
+     trial-balance.html (試算表)
+     テキスト中心の inline 検索フォームを縦積みにする
+     ================================================================ */
+
+  .search-form {
+    text-align: left !important;
+    padding: 12px !important;
+  }
+
+  /* trial-balance の検索フォームは label/input が直接子要素 */
+  .search-form > label {
+    display: block !important;
+    margin: 6px 0 2px !important;
+  }
+
+  .search-form > input[type="text"],
+  .search-form > input[type="date"],
+  .search-form > input[type="number"] {
+    display: block !important;
+    width: 100% !important;
+    margin: 0 0 8px 15px !important;
+    box-sizing: border-box !important;
+  }
+
+  .search-form > button {
+    display: inline-block !important;
+    margin: 4px 4px 0 0 !important;
+    width: auto !important;
+    min-width: 80px;
+  }
+
+  /* ================================================================
+     nenkin-portal.html (社会保険電子文書)
+     ================================================================ */
+
+  .page-header {
+    flex-direction: column !important;
+    align-items: flex-start !important;
+    gap: 10px !important;
+  }
+
+  .upload-zone {
+    padding: 20px 16px !important;
+  }
+
+  /* フィルターバー: wrapping は既存スタイルで対応済み、幅を補完 */
+  .filter-bar {
+    gap: 8px !important;
+  }
+
+  .filter-select {
+    width: 100% !important;
+    box-sizing: border-box !important;
+  }
+
+  /* ================================================================
+     payroll-employees.html / payroll-settings.html (タブ UI)
+     ================================================================ */
+
+  .nav-tabs {
+    flex-wrap: wrap !important;
+    justify-content: flex-start !important;
+    gap: 6px !important;
+    border-bottom: none !important;
+  }
+
+  .nav-tab {
+    padding: 8px 14px !important;
+    font-size: 0.85rem !important;
+    border-radius: 6px !important;
+  }
+
+  /* container の余白縮小 */
+  .container {
+    margin: 10px !important;
+    padding: 16px 12px !important;
+    border-radius: 10px !important;
+  }
+
+  /* ================================================================
+     payroll-settings.html (2/3カラムフォームグリッド → 1カラム)
+     ================================================================ */
+
+  .form-row {
+    display: flex !important;
+    flex-direction: column !important;
+    gap: 10px !important;
+  }
+
+  .form-row-3 {
+    display: flex !important;
+    flex-direction: column !important;
+    gap: 10px !important;
+  }
+
+  .form-group {
+    width: 100%;
+  }
+
+  .form-group input,
+  .form-group select,
+  .form-group textarea {
+    width: 100% !important;
+    box-sizing: border-box !important;
+  }
+
+  /* ================================================================
+     payroll-calculation.html (月次給与計算)
+     ================================================================ */
+
+  /* フィルター行のラベルを縦積み */
+  .filters {
+    display: flex !important;
+    flex-direction: column !important;
+    gap: 8px !important;
+    padding: 12px !important;
+  }
+
+  .filters label {
+    display: flex !important;
+    flex-direction: column !important;
+    gap: 4px !important;
+    margin-right: 0 !important;
+    width: 100%;
+  }
+
+  .filters input,
+  .filters select {
+    width: 100% !important;
+    box-sizing: border-box !important;
+  }
+
+}

frontend/egov.html

@@ -5,6 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <title>e-Gov 電子送達 – NJTS</title>
     <script src="js/auth.js"></script>
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       * {
         box-sizing: border-box;

frontend/index.html

@@ -2,8 +2,10 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>NJTS 会計システム - メイン</title>
     <link rel="stylesheet" href="css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <script src="js/auth.js"></script>
     <style>
       body {
@@ -79,6 +81,50 @@
       .logout-btn:hover {
         background: #c82333;
       }
+      .change-pw-btn {
+        padding: 8px 12px;
+        background: #6c757d;
+        color: white;
+        border: none;
+        border-radius: 4px;
+        cursor: pointer;
+        font-size: 13px;
+      }
+      .change-pw-btn:hover { background: #545b62; }
+      /* パスワード変更モーダル */
+      .modal-overlay {
+        display: none;
+        position: fixed;
+        inset: 0;
+        background: rgba(0,0,0,0.5);
+        z-index: 1000;
+        justify-content: center;
+        align-items: center;
+      }
+      .modal-overlay.active { display: flex; }
+      .modal-box {
+        background: white;
+        border-radius: 10px;
+        padding: 32px;
+        width: 360px;
+        box-shadow: 0 10px 30px rgba(0,0,0,0.3);
+      }
+      .modal-box h3 { margin: 0 0 20px; }
+      .modal-box .form-group { margin-bottom: 14px; }
+      .modal-box label { display: block; margin-bottom: 5px; font-size: 13px; font-weight: 600; color: #333; }
+      .modal-box input[type="password"] {
+        width: 100%; padding: 10px; border: 1px solid #ddd;
+        border-radius: 5px; font-size: 14px; box-sizing: border-box;
+      }
+      .modal-box .btn-row { display: flex; gap: 10px; margin-top: 20px; }
+      .modal-box .btn-row button { flex: 1; padding: 10px; border: none; border-radius: 5px; cursor: pointer; font-size: 14px; }
+      .modal-box .btn-submit { background: #007bff; color: white; }
+      .modal-box .btn-submit:hover { background: #0056b3; }
+      .modal-box .btn-cancel { background: #e9ecef; color: #333; }
+      .modal-box .btn-cancel:hover { background: #d0d5db; }
+      .modal-msg { padding: 8px 12px; border-radius: 4px; margin-bottom: 12px; display: none; font-size: 13px; }
+      .modal-msg.error { background: #fee; color: #c33; border: 1px solid #fcc; }
+      .modal-msg.success { background: #efe; color: #3a3; border: 1px solid #cfc; }
     </style>
   </head>
   <body>
@@ -86,10 +132,35 @@
       <h1>NJTS</h1>
       <div class="user-info">
         <span>ユーザー: <strong id="username">読み込み中...</strong></span>
+        <button class="change-pw-btn" onclick="openChangePw()">パスワード変更</button>
         <button class="logout-btn" onclick="logout()">ログアウト</button>
       </div>
     </header>
 
+    <!-- パスワード変更モーダル -->
+    <div class="modal-overlay" id="changePwModal">
+      <div class="modal-box">
+        <h3>🔒 パスワード変更</h3>
+        <div class="modal-msg" id="changePwMsg"></div>
+        <div class="form-group">
+          <label>現在のパスワード</label>
+          <input type="password" id="cpCurrent" placeholder="現在のパスワード" />
+        </div>
+        <div class="form-group">
+          <label>新しいパスワード（8文字以上）</label>
+          <input type="password" id="cpNew" placeholder="新しいパスワード" />
+        </div>
+        <div class="form-group">
+          <label>新しいパスワード（確認）</label>
+          <input type="password" id="cpConfirm" placeholder="もう一度入力" />
+        </div>
+        <div class="btn-row">
+          <button class="btn-submit" onclick="submitChangePw()">変更する</button>
+          <button class="btn-cancel" onclick="closeChangePw()">キャンセル</button>
+        </div>
+      </div>
+    </div>
+
     <main class="grid">
       <section class="card">
         <h2>会計システム</h2>
@@ -142,6 +213,56 @@
         }
       });
 
+      // パスワード変更モーダル
+      function openChangePw() {
+        document.getElementById("cpCurrent").value = "";
+        document.getElementById("cpNew").value = "";
+        document.getElementById("cpConfirm").value = "";
+        const msg = document.getElementById("changePwMsg");
+        msg.style.display = "none";
+        document.getElementById("changePwModal").classList.add("active");
+      }
+      function closeChangePw() {
+        document.getElementById("changePwModal").classList.remove("active");
+      }
+      function showChangePwMsg(text, isError) {
+        const msg = document.getElementById("changePwMsg");
+        msg.textContent = text;
+        msg.className = "modal-msg " + (isError ? "error" : "success");
+        msg.style.display = "block";
+      }
+      async function submitChangePw() {
+        const current = document.getElementById("cpCurrent").value;
+        const newPw   = document.getElementById("cpNew").value;
+        const confirm = document.getElementById("cpConfirm").value;
+        const user    = getCurrentUser();
+        if (!current || !newPw || !confirm) {
+          showChangePwMsg("すべての項目を入力してください", true); return;
+        }
+        if (newPw.length < 8) {
+          showChangePwMsg("新しいパスワードは8文字以上にしてください", true); return;
+        }
+        if (newPw !== confirm) {
+          showChangePwMsg("新しいパスワードが一致しません", true); return;
+        }
+        try {
+          const res = await fetch("/api/users/change-password", {
+            method: "POST",
+            headers: { "Content-Type": "application/json" },
+            body: JSON.stringify({ username: user.username, current_password: current, new_password: newPw })
+          });
+          const data = await res.json();
+          if (res.ok) {
+            showChangePwMsg("パスワードを変更しました。再ログインしてください", false);
+            setTimeout(() => { logout(); }, 2000);
+          } else {
+            showChangePwMsg(data.detail || "変更に失敗しました", true);
+          }
+        } catch (e) {
+          showChangePwMsg("エラー: " + e.message, true);
+        }
+      }
+
       // dropdown toggle
       const toggle = document.getElementById("accountingToggle");
       const menu = document.getElementById("accountingMenu");

frontend/journal-edit.html

@@ -2,7 +2,9 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
+    <link rel="stylesheet" href="/css/mobile.css" />
     <title>修正仕訳入力</title>
     <style>
       body {

frontend/journal-entry.html

@@ -2,7 +2,9 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
+    <link rel="stylesheet" href="/css/mobile.css" />
     <title>仕訳入力</title>
     <style>
       body {

frontend/journal-list.html

@@ -2,7 +2,9 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
+    <link rel="stylesheet" href="/css/mobile.css" />
     <title>仕訳一覧</title>
     <style>
       body {

frontend/journal-view.html

@@ -2,7 +2,9 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
+    <link rel="stylesheet" href="/css/mobile.css" />
     <title>仕訳詳細</title>
     <style>
       body {

frontend/journal.html

@@ -2,9 +2,11 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
     <title>仕訳入力</title>
     <link rel="stylesheet" href="css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
   </head>
   <body>
     <h1>仕訳入力</h1>

frontend/js/auth.js

@@ -1,41 +1,59 @@
 /**
- * 认证和会话管理
+ * 認証・セッション管理
  */
 
-// 检查用户是否已登录
+// ──────────────────────────────────────
+// ページ描画前に即座に認証確認（フラッシュ防止）
+// ──────────────────────────────────────
+(function () {
+  if (!window.location.pathname.includes("login.html")) {
+    if (!localStorage.getItem("currentUser")) {
+      // ページが見えてしまわないよう即座に非表示にしてからリダイレクト
+      document.documentElement.style.visibility = "hidden";
+      window.location.replace("/login.html");
+    }
+  }
+})();
+
+// bfcache（戻る/進むボタン）対応
+// ブラウザがキャッシュからページを復元した場合も認証を再確認する
+window.addEventListener("pageshow", function (event) {
+  if (!window.location.pathname.includes("login.html")) {
+    if (!localStorage.getItem("currentUser")) {
+      // bfcacheから復元されたページを即座に非表示にしてリダイレクト
+      document.documentElement.style.visibility = "hidden";
+      window.location.replace("/login.html");
+    }
+  }
+});
+
 function checkAuth() {
   const user = localStorage.getItem("currentUser");
   if (!user) {
-    // 用户未登录，重定向到登录页面
+    window.location.replace("/login.html");
-    window.location.href = "/login.html";
     return false;
   }
   return true;
 }
 
-// 获取当前登录的用户信息
 function getCurrentUser() {
   const user = localStorage.getItem("currentUser");
   return user ? JSON.parse(user) : null;
 }
 
-// 保存用户信息（登录时使用）
 function setCurrentUser(userData) {
   localStorage.setItem("currentUser", JSON.stringify(userData));
 }
 
-// 注销用户
 function logout() {
   localStorage.removeItem("currentUser");
-  window.location.href = "/login.html";
+  sessionStorage.clear();
+  // replace() を使うことでログイン前の履歴に戻れなくなる
+  window.location.replace("/login.html");
 }
 
-// 在页面加载时检查认证（仅在非登录页面使用）
 document.addEventListener("DOMContentLoaded", function () {
-  const currentPage = window.location.pathname;
+  if (!window.location.pathname.includes("login.html")) {
-
-  // 排除登录页面的检查
-  if (!currentPage.includes("login.html")) {
     checkAuth();
   }
 });

frontend/ledger.html

@@ -2,9 +2,11 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
     <title>元帳</title>
     <link rel="stylesheet" href="css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
   </head>
   <body>
     <h1 id="account-title">元帳</h1>

frontend/login.html

@@ -4,6 +4,7 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>NJTS 会計システム - ログイン</title>
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       * {
         margin: 0;
@@ -108,16 +109,6 @@
         box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
       }
 
-      .btn-register {
-        background: transparent;
-        color: #667eea;
-        border: 2px solid #667eea;
-      }
-
-      .btn-register:hover {
-        background: #f0f0ff;
-      }
-
       .message {
         padding: 12px;
         border-radius: 5px;
@@ -138,32 +129,6 @@
         border: 1px solid #cfc;
       }
 
-      .toggle-form {
-        text-align: center;
-        margin-top: 20px;
-        font-size: 14px;
-        color: #666;
-      }
-
-      .toggle-form a {
-        color: #667eea;
-        text-decoration: none;
-        cursor: pointer;
-        font-weight: 500;
-      }
-
-      .toggle-form a:hover {
-        text-decoration: underline;
-      }
-
-      .form {
-        display: none;
-      }
-
-      .form.active {
-        display: block;
-      }
-
       .loading {
         display: none;
         text-align: center;
@@ -181,7 +146,7 @@
       </div>
 
       <!-- ログインフォーム -->
-      <div id="loginForm" class="form active">
+      <div id="loginForm">
         <div id="messageLogin" class="message"></div>
 
         <div class="form-group">
@@ -208,47 +173,8 @@
           <button class="btn-login" onclick="handleLogin()">ログイン</button>
         </div>
 
-        <div class="toggle-form">
-          新規登録？
-          <a onclick="toggleForm()">アカウント作成</a>
-        </div>
-
         <div class="loading" id="loginLoading">処理中...</div>
       </div>
-
-      <!-- 登録フォーム -->
-      <div id="registerForm" class="form">
-        <div id="messageRegister" class="message"></div>
-
-        <div class="form-group">
-          <label for="regUsername">ユーザー名</label>
-          <input
-            type="text"
-            id="regUsername"
-            placeholder="ユーザー名を入力"
-            required
-          />
-        </div>
-
-        <div class="form-group">
-          <label for="regPassword">パスワード</label>
-          <input
-            type="password"
-            id="regPassword"
-            placeholder="6文字以上で設定"
-            required
-          />
-        </div>
-
-        <div class="button-group">
-          <button class="btn-login" onclick="handleRegister()">登録</button>
-          <button class="btn-register" onclick="toggleForm()">
-            キャンセル
-          </button>
-        </div>
-
-        <div class="loading" id="registerLoading">処理中...</div>
-      </div>
     </div>
 
     <script>
@@ -330,82 +256,19 @@
         }
       }
 
-      async function handleRegister() {
+      // EnterキーでログインできるようにEnterキーをバインド
-        const username = document.getElementById("regUsername").value;
-        const password = document.getElementById("regPassword").value;
-
-        if (!username || !password) {
-          showMessage(
-            "messageRegister",
-            "ユーザー名とパスワードを入力してください",
-            true,
-          );
-          return;
-        }
-
-        if (password.length < 6) {
-          showMessage(
-            "messageRegister",
-            "パスワードは6文字以上である必要があります",
-            true,
-          );
-          return;
-        }
-
-        const loadingEl = document.getElementById("registerLoading");
-        loadingEl.style.display = "block";
-
-        try {
-          const response = await fetch("/api/users/register", {
-            method: "POST",
-            headers: {
-              "Content-Type": "application/json",
-            },
-            body: JSON.stringify({ username, password }),
-          });
-
-          const data = await response.json();
-
-          if (response.ok) {
-            showMessage(
-              "messageRegister",
-              "登録が完了しました。ログインしてください",
-              false,
-            );
-            setTimeout(() => {
-              toggleForm();
-              document.getElementById("loginUsername").value = username;
-              document.getElementById("loginPassword").value = "";
-            }, 2000);
-          } else {
-            showMessage(
-              "messageRegister",
-              data.detail || "登録に失敗しました",
-              true,
-            );
-          }
-        } catch (error) {
-          showMessage(
-            "messageRegister",
-            "エラーが発生しました: " + error.message,
-            true,
-          );
-        } finally {
-          loadingEl.style.display = "none";
-        }
-      }
-
-      // Enterキーでログイン/登録
       document.addEventListener("keypress", (e) => {
         if (e.key === "Enter") {
-          const loginForm = document.getElementById("loginForm");
-          if (loginForm.classList.contains("active")) {
           handleLogin();
-          } else {
-            handleRegister();
-          }
         }
       });
+
+      // ログインページから後退ボタンで離脱できないようにする
+      // （ログアウト後に戻るボタンでメニューが見えてしまう問題の対策）
+      history.pushState(null, "", window.location.href);
+      window.addEventListener("popstate", function () {
+        history.pushState(null, "", window.location.href);
+      });
     </script>
   </body>
 </html>

frontend/nenkin-portal.html

@@ -6,6 +6,7 @@
   <title>社会保険電子文書ポータル</title>
   <script src="js/auth.js"></script>
   <link rel="stylesheet" href="css/style.css" />
+  <link rel="stylesheet" href="/css/mobile.css" />
   <style>
     body {
       font-family: system-ui, -apple-system, "Yu Gothic UI", "Hiragino Kaku Gothic ProN", "メイリオ", sans-serif;

frontend/opening_balance.html

@@ -2,9 +2,11 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
     <title>期首残高入力</title>
     <link rel="stylesheet" href="css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
   </head>
   <body>
     <h1>期首残高入力</h1>

frontend/payroll-calculation.html

@@ -12,6 +12,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>給与管理 - 月次給与計算</title>
     <link rel="stylesheet" href="/css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       .container {
         max-width: 1440px;

frontend/payroll-employees.html

@@ -12,6 +12,7 @@
       rel="stylesheet"
     />
     <link rel="stylesheet" href="/css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       body {
         font-family: "Noto Sans JP", Arial, sans-serif;

frontend/payroll-salary-settings.html

@@ -6,6 +6,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>給与管理 - 給与設定</title>
     <link rel="stylesheet" href="/css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       .employee-select {
         margin-bottom: 20px;

frontend/payroll-settings.html

@@ -6,6 +6,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>給与管理 - 設定</title>
     <link rel="stylesheet" href="/css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       .nav-tabs {
         display: flex;

frontend/payroll.html

@@ -6,6 +6,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>給与管理システム</title>
     <link rel="stylesheet" href="/css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       .menu-grid {
         display: grid;

frontend/trial-balance.html

@@ -2,8 +2,11 @@
 <html lang="ja">
   <head>
     <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="js/auth.js"></script>
     <title>試算表</title>
+    <link rel="stylesheet" href="css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       body {
         font-family: "MS Gothic", "Meiryo", sans-serif;

frontend/withholding-slip.html

@@ -9,6 +9,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>給与所得の源泉徴収票</title>
     <link rel="stylesheet" href="/css/style.css" />
+    <link rel="stylesheet" href="/css/mobile.css" />
     <style>
       /* ===== 画面UI ===== */
       body { font-family: 'MS Gothic', 'Meiryo', sans-serif; }