diff --git a/change.js b/change.js
index 65e11b4..68ec812 100644
--- a/change.js
+++ b/change.js
@@ -4,6 +4,7 @@
     let cssbtn1 = document.getElementById("css1");
     let cssbtn2 = document.getElementById("css2");
     let cssbtn3 = document.getElementById("css3");
+    let cssbtn4 = document.getElementById("css4");
     
     cssbtn1.addEventListener("click", (e) => {  
         if (newcss) return;
@@ -30,6 +31,14 @@
             head.appendChild(newcss);	// link要素を追加
             });
 
+            cssbtn4.addEventListener("click", (e) => {  
+                if (newcss) return;
+                newcss = document.createElement("link");
+                newcss.rel = "stylesheet";
+                newcss.href = "new4.css";
+                head.appendChild(newcss);	// link要素を追加
+                });
+
         let unlbtn = document.getElementById("unl");
         unlbtn.addEventListener("click", (e) => {
             if (newcss) {
diff --git a/index.html b/index.html
index 40d41f4..380e0a8 100644
--- a/index.html
+++ b/index.html
@@ -138,6 +138,9 @@
                 <li>
                   <p><button type="button" id="css3" class="bg-change">背景3</button></p>
               </li>
+              <li>
+                <p><button type="button" id="css4" class="bg-change">背景4</button></p>
+            </li>
             </ul>
         </div>
         <!--ここまでメニュー-->
diff --git a/jstrr.css b/jstrr.css
index 90de208..f8cbc43 100644
--- a/jstrr.css
+++ b/jstrr.css
@@ -76,6 +76,7 @@
     background-size: cover;
     width: 100%;
     z-index: 999;
+    display: none;
 }
 div.login-item{
     position: absolute;
diff --git a/new4.css b/new4.css
index e69de29..9b932f7 100644
--- a/new4.css
+++ b/new4.css
@@ -0,0 +1,4 @@
+body {    
+    background-image: url(jstrr4.png);
+    background-color: rgb(241,89,30);
+}
\ No newline at end of file