diff --git a/app/main/services/window-process-management-service.ts b/app/main/services/window-process-management-service.ts
index 6f88daac..662b5ea5 100644
--- a/app/main/services/window-process-management-service.ts
+++ b/app/main/services/window-process-management-service.ts
@@ -10,6 +10,7 @@ import {
 } from "electron";
 import os from "os";
 import path, { join, posix } from "path";
+import fs from "fs";
 
 import { errorcatching } from "@/base/error";
 import { Eventable } from "@/base/event";
@@ -20,6 +21,7 @@ import {
   PreferenceService,
 } from "@/common/services/preference-service";
 import { WindowStorage } from "@/main/window-storage";
+import { FileSystemService, IFileSystemService } from "./filesystem-service";
 
 interface WindowOptions extends BrowserWindowConstructorOptions {
   entry: string;
@@ -47,7 +49,8 @@ export class WindowProcessManagementService extends Eventable<IWindowProcessMana
   public browserWindows: WindowStorage;
 
   constructor(
-    @IPreferenceService private readonly _preferenceService: PreferenceService
+    @IPreferenceService private readonly _preferenceService: PreferenceService,
+    @IFileSystemService private readonly _fileSystemService: FileSystemService
   ) {
     super("windowProcessManagementService", {
       serviceReady: "",
@@ -162,6 +165,16 @@ export class WindowProcessManagementService extends Eventable<IWindowProcessMana
       });
     }
 
+    // Insert custom CSS
+    const configDir = this._fileSystemService.getSystemPath(
+      "userData",
+      Process.main
+    );
+    if (fs.existsSync(path.join(configDir, `${id}.css`))) {
+      const css = fs.readFileSync(path.join(configDir, `${id}.css`), "utf-8");
+      this.insertCustomCSS(id, css);
+    }
+
     this.fire({ [id]: "created" });
   }
 
diff --git a/app/renderer/ui/preference-view/mainview-view.vue b/app/renderer/ui/preference-view/mainview-view.vue
index 7b5b62f0..8318fd5c 100644
--- a/app/renderer/ui/preference-view/mainview-view.vue
+++ b/app/renderer/ui/preference-view/mainview-view.vue
@@ -169,14 +169,6 @@ onMounted(() => {
 const updatePref = (key: keyof IPreferenceStore, value: unknown) => {
   preferenceService.set({ [key]: value });
 };
-
-const onInsertMainCssCliecked = async () => {
-  await PLMainAPI.windowProcessManagementService.insertCustomCSS(Process.renderer, prefState.customMainWindowCSS);
-};
-
-const onInsertQuickPasteCssCliecked = async () => {
-  await PLMainAPI.windowProcessManagementService.insertCustomCSS(Process.quickpaste, prefState.customQuickPasteCSS);
-};
 </script>
 
 <template>
@@ -241,37 +233,5 @@ const onInsertQuickPasteCssCliecked = async () => {
         @event:next-click="onMoveNextClicked(index, false)"
       />
     </div>
-
-    <div class="text-base font-semibold mt-4">
-        {{ $t("preference.custom") + " Main CSS" }}
-    </div>
-    <div class="flex justify-between flex-col gap-3">
-      <textarea
-        class="w-full h-32 p-2 mt-2 bg-neutral-200 dark:bg-neutral-700 text-neutral-800 dark:text-neutral-300"
-        v-model="prefState.customMainWindowCSS"
-      ></textarea>
-      <button
-        class="flex h-8 w-[5.5rem] text-center rounded-md bg-neutral-200 dark:bg-neutral-600 hover:bg-neutral-300 hover:dark:bg-neutral-600"
-        @click="onInsertMainCssCliecked"
-      >
-        {{ $t("menu.save") }}
-      </button>
-    </div>
-
-    <div class="text-base font-semibold mt-4">
-        {{ $t("preference.custom") + $t("preference.mainview") + " Quick Paste CSS" }}
-        </div>
-        <div class="flex justify-between flex-col gap-3">
-          <textarea
-            class="w-full h-32 p-2 mt-2 bg-neutral-200 dark:bg-neutral-700 text-neutral-800 dark:text-neutral-300"
-            v-model="prefState.customQuickPasteCSS"
-          ></textarea>
-          <button
-            class="flex h-8 w-[5.5rem] text-center rounded-md bg-neutral-200 dark:bg-neutral-600 hover:bg-neutral-300 hover:dark:bg-neutral-600"
-            @click="onInsertQuickPasteCssCliecked"
-          >
-            {{ $t("menu.save") }}
-          </button>
-      </div>
   </div>
 </template>