diff --git a/book-rent/src/main/java/com/example/demo/config/CustomAuthenticationFailureHandler.java b/book-rent/src/main/java/com/example/demo/config/CustomAuthenticationFailureHandler.java
index be6c000..9810c7f 100644
--- a/book-rent/src/main/java/com/example/demo/config/CustomAuthenticationFailureHandler.java
+++ b/book-rent/src/main/java/com/example/demo/config/CustomAuthenticationFailureHandler.java
@@ -14,46 +14,59 @@ import com.example.demo.service.LoginAttemptService;
  
 // ログイン失敗時の処理
 @Component
-public class CustomAuthenticationFailureHandler extends SimpleUrlAuthenticationFailureHandler {
+public class CustomAuthenticationFailureHandler
+        extends SimpleUrlAuthenticationFailureHandler {
  
-	private LoginAttemptService loginAttemptService;
+    private final LoginAttemptService loginAttemptService;
  
-	public CustomAuthenticationFailureHandler(LoginAttemptService loginAttemptService) {
-		this.loginAttemptService = loginAttemptService;
-	}
+    public CustomAuthenticationFailureHandler(
+            LoginAttemptService loginAttemptService) {
+        this.loginAttemptService = loginAttemptService;
+    }
  
-	@Override
-	public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,
-			AuthenticationException exception) throws IOException, ServletException {
+    @Override
+    public void onAuthenticationFailure(
+            HttpServletRequest request,
+            HttpServletResponse response,
+            AuthenticationException exception)
+            throws IOException, ServletException {
  
-		// 画面から入力されたメールアドレスを取得
-		String mailAddress = request.getParameter("mailAddress");
+        // 画面から入力されたメールアドレスを取得
+        String mailAddress = request.getParameter("mailAddress");
  
-		if (mailAddress != null && !mailAddress.isBlank()) {
-			String mail = mailAddress.trim();
+        // メールアドレスが空欄の場合
+        if (mailAddress == null || mailAddress.isBlank()) {
+            getRedirectStrategy().sendRedirect(
+                    request, response, "/login?error=empty");
+            return;
+        }
  
-			if (loginAttemptService.isBlocked(mail)) {
-				getRedirectStrategy().sendRedirect(
-						request, response, "/login?error=locked");
-				return;
-			}
+        String mail = mailAddress.trim();
  
-			// 失敗回数を１増やす
-			loginAttemptService.loginFailed(mail);
+        // すでにロックされている場合
+        if (loginAttemptService.isBlocked(mail)) {
+            getRedirectStrategy().sendRedirect(
+                    request, response, "/login?error=locked");
+            return;
+        }
  
-			// すでにロック中なら失敗回数を増やさない
-			if (loginAttemptService.isBlocked(mail)) {
-				getRedirectStrategy().sendRedirect(
-						request, response, "/login?error=locked");
-				return;
-			}
+        // ログイン失敗回数を増やす
+        loginAttemptService.loginFailed(mail);
  
-			// あと何回失敗されるとロックされるか取得
-			int remaining = loginAttemptService.getRemainingAttempts(mail);
+        // 失敗回数の上限に達した場合
+        if (loginAttemptService.isBlocked(mail)) {
+            getRedirectStrategy().sendRedirect(
+                    request, response, "/login?error=locked");
+            return;
+        }
  
-			getRedirectStrategy().sendRedirect(
-					request, response, "/login?error=failed&remaining=" + remaining);
-		}
+        // 残りのログイン試行回数を取得
+        int remaining =
+                loginAttemptService.getRemainingAttempts(mail);
  
-	}
+        getRedirectStrategy().sendRedirect(
+                request, response,
+                "/login?error=failed&remaining=" + remaining);
+    }
 }
+ 
\ No newline at end of file
diff --git a/book-rent/src/main/resources/static/css/style.css b/book-rent/src/main/resources/static/css/style.css
index 6a1a62f..c41bc01 100644
--- a/book-rent/src/main/resources/static/css/style.css
+++ b/book-rent/src/main/resources/static/css/style.css
@@ -126,4 +126,9 @@ th { background: #eaf4f6; }
  
 .page-number:hover {
     background: #d5edf1;
+}
+.page-number.active {
+    background: #176a78;
+    color: #fff;
+    border-color: #176a78;
 }
\ No newline at end of file
diff --git a/book-rent/src/main/resources/templates/bookList.html b/book-rent/src/main/resources/templates/bookList.html
index 42ad7d3..3efd268 100644
--- a/book-rent/src/main/resources/templates/bookList.html
+++ b/book-rent/src/main/resources/templates/bookList.html
@@ -65,6 +65,7 @@
 			   th:href="@{/books(page=${bookPage.number-1}, nmBook=${nmBook}, publisher=${publisher}, note=${note})}">前へ</a>
 			<span th:each="pageNum : ${pageNumbers}">
 			    <a class="page-number"
+				   th:classappend="${pageNum == bookPage.number} ? ' active' : ''"
 				   th:href="@{/books(page=${pageNum}, nmBook=${nmBook}, publisher=${publisher}, note=${note})}"
 			       th:text="${pageNum + 1}"></a>
 			</span>