diff --git a/src/app.lisp b/src/app.lisp
index 39e40ae..cebe764 100644
--- a/src/app.lisp
+++ b/src/app.lisp
@@ -8,7 +8,7 @@
   (:export #:*app*))
 (in-package #:hp/app)
 
-(defparameter *app* (jg:make-app :address "localhost"
+(defparameter *app* (jg:make-app :address env:*address*
                                  :port env:*port*))
 
 (fbr:assign-routes *app* :system "hp" :directory "src/routes")
diff --git a/src/env.lisp b/src/env.lisp
index 9b9179c..da55c39 100644
--- a/src/env.lisp
+++ b/src/env.lisp
@@ -2,7 +2,8 @@
   (:use #:cl)
   (:export #:dev-mode-p
            #:prod-mode-p
-           #:*port*))
+           #:*port*
+           #:*address*))
 (in-package #:hp/env)
 
 (defmacro defenv (name env &key default parser)
@@ -14,6 +15,7 @@
              ,default)))))
 
 (defenv *env* "HP_ENV" :default "dev")
+(defenv *address* "HP_ADDRESS" :default "localhost")
 (defenv *port* "HP_PORT" :default 3000 :parser #'parse-integer)
 
 (defun dev-mode-p ()
diff --git a/src/main.lisp b/src/main.lisp
index cd75331..c83f1f6 100644
--- a/src/main.lisp
+++ b/src/main.lisp
@@ -7,16 +7,19 @@
                 #:*app*)
   (:export #:start
            #:stop
-           #:update))
+           #:reload))
 (in-package #:hp)
 
 (defun start ()
-  (jg:start *app*))
+  (jg:start *app*)
+  (when (env:dev-mode-p)
+    (uiop:run-program (format nil "open http://~a:~a"
+                              env:*address* env:*port*))))
 
 (defun stop ()
   (jg:stop *app*))
 
-(defun update ()
+(defun reload ()
   (stop)
   (ql:quickload :hp/app)
   (start))
diff --git a/src/routes/not-found.lisp b/src/routes/not-found.lisp
index f3d9202..d9371c5 100644
--- a/src/routes/not-found.lisp
+++ b/src/routes/not-found.lisp
@@ -7,12 +7,16 @@
 
 (defparameter *metadata*
   '(:title "404 Not Found"
-    :description "お探しのページは見つかりませんでした。"))
+    :description "お探しのページは削除されたか、URLが間違っている可能性があります。"))
 
 (defcomp page ()
   (hsx
-   (h1 :class "text-red-600"
-     "404 Not Found")))
+   (div :class "flex flex-col justify-center items-center h-full gap-4"
+     (h1 :class "text-2xl text-red-600"
+       "404 Not Found")
+     (p (getf *metadata* :description))
+     (a :href "/" :class "text-pink-600"
+       "トップページに戻る"))))
 
 (defun handle-not-found ()
   (jg:set-response-status :not-found)