diff --git a/src/main/java/com/keke125/pixel/views/generateimage/PixelTransformView.java b/src/main/java/com/keke125/pixel/views/generateimage/PixelTransformView.java
index c88918d..f70a612 100644
--- a/src/main/java/com/keke125/pixel/views/generateimage/PixelTransformView.java
+++ b/src/main/java/com/keke125/pixel/views/generateimage/PixelTransformView.java
@@ -44,8 +44,6 @@
 import org.apache.commons.codec.digest.DigestUtils;
 import org.apache.commons.io.FilenameUtils;
 import org.apache.tika.Tika;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Value;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/src/main/java/com/keke125/pixel/views/signup/SignupView.java b/src/main/java/com/keke125/pixel/views/signup/SignupView.java
index bbe1ba2..9c2fb10 100644
--- a/src/main/java/com/keke125/pixel/views/signup/SignupView.java
+++ b/src/main/java/com/keke125/pixel/views/signup/SignupView.java
@@ -29,7 +29,6 @@
 import com.vaadin.flow.server.auth.AnonymousAllowed;
 import org.apache.tika.Tika;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Value;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -67,7 +66,7 @@ public class SignupView extends VerticalLayout {
     // The default image size limit for new sign-up users
     // you can modify this value
     // @Value("{user.image.size.limit:30}")
-    private double defaultImageSizeLimit;
+    private final double defaultImageSizeLimit;
     private final Span dropLabel;
     private final EmailField emailField;
     private final Span errorMessage;
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index 5884f36..1ec76ed 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -9,6 +9,7 @@ spring.datasource.url=${PAFW_DB_URL}
 spring.datasource.username=${PAFW_DB_USER}
 spring.datasource.password=${PAFW_DB_PASSWORD}
 spring.datasource.driver-class-name=org.mariadb.jdbc.Driver
+
 # upload limit
 # you need modify this value if you want upload bigger image
 spring.servlet.multipart.max-file-size=30MB
@@ -25,8 +26,11 @@ app.maxAvatarSizeInMegaBytes=3
 # The default image size limit for new sign-up users
 # you can modify this value
 app.newSignupImageSizeLimit=30
+# security
+# password encoder
 # BCrypt pbkdf2 argon2
 app.idForEncode=argon2
+# website detail
 # website location country
 app.webCountry=Taiwan
 # website name
@@ -42,6 +46,7 @@ app.adminContactEmail=admin@example.com
 # login form additional information
 app.loginInfoTC=\u5982\u679C\u9047\u5230\u767B\u5165\u554F\u984C\uFF0C\u8ACB\u806F\u7E6B admin@example.com
 app.loginInfoEN=Contact admin@example.com if you're experiencing issues logging into your account.
+# other setting
 logging.level.org.atmosphere=warn
 spring.mustache.check-template-location=false
 # Launch the default browser when starting the application in development mode