delete some unused files

background.js

@@ -1,5 +0,0 @@
-chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
-    if (message.action === "openTab") {
-        chrome.tabs.create({url: message.url});
-    }
-});

manifest.json

@@ -13,12 +13,8 @@
   },
   "permissions": [
     "scripting",
-    "activeTab",
-    "tabs"
+    "activeTab"
   ],
-  "background": {
-    "service_worker": "background.js"
-  },
   "content_scripts": [
     {
       "matches": [

popup.css

@@ -84,12 +84,6 @@ body {
   gap: 10px; /* 如果需要，可以添加这一行以在子元素之间创建一些空间 */
 }
 
-.footer button {
-  font-size: inherit; /* 这行代码使按钮的字体大小继承自其父元素，即.footer */
-  background-color: #383E46;
-  border-color: #78838F;
-}
-
 button#remove-checkboxes {
   background-color: #badb34;
   border-color: #b6b929;