diff --git a/src/components/layout/use-custom-theme.ts b/src/components/layout/use-custom-theme.ts
index 7682b0a96..3e8e7c916 100644
--- a/src/components/layout/use-custom-theme.ts
+++ b/src/components/layout/use-custom-theme.ts
@@ -18,6 +18,61 @@ import { useVerge } from "@/hooks/use-verge";
 import { defaultDarkTheme, defaultTheme } from "@/pages/_theme";
 import { useSetThemeMode, useThemeMode } from "@/services/states";
 
+const CSS_INJECTION_SCOPE_ROOT = "[data-css-injection-root]";
+const CSS_INJECTION_SCOPE_LIMIT =
+  ':is(.monaco-editor .view-lines, .monaco-editor .view-line, .monaco-editor .margin, .monaco-editor .margin-view-overlays, .monaco-editor .view-overlays, .monaco-editor [class^="mtk"], .monaco-editor [class*=" mtk"])';
+const TOP_LEVEL_AT_RULES = [
+  "@charset",
+  "@import",
+  "@namespace",
+  "@font-face",
+  "@keyframes",
+  "@counter-style",
+  "@page",
+  "@property",
+  "@font-feature-values",
+  "@color-profile",
+];
+let cssScopeSupport: boolean | null = null;
+
+const canUseCssScope = () => {
+  if (cssScopeSupport !== null) {
+    return cssScopeSupport;
+  }
+  if (typeof document === "undefined") {
+    return false;
+  }
+  try {
+    const testStyle = document.createElement("style");
+    testStyle.textContent = "@scope (:root) { }";
+    document.head.appendChild(testStyle);
+    cssScopeSupport = !!testStyle.sheet?.cssRules?.length;
+    document.head.removeChild(testStyle);
+  } catch {
+    cssScopeSupport = false;
+  }
+  return cssScopeSupport;
+};
+
+const wrapCssInjectionWithScope = (css?: string) => {
+  if (!css?.trim()) {
+    return "";
+  }
+  const lowerCss = css.toLowerCase();
+  const hasTopLevelOnlyRule = TOP_LEVEL_AT_RULES.some((rule) =>
+    lowerCss.includes(rule),
+  );
+  if (hasTopLevelOnlyRule) {
+    return null;
+  }
+  const scopeRoot = CSS_INJECTION_SCOPE_ROOT;
+  const scopeLimit = CSS_INJECTION_SCOPE_LIMIT;
+  const scopedBlock = `@scope (${scopeRoot}) to (${scopeLimit}) {
+${css}
+}`;
+  return scopedBlock;
+};
+
 const languagePackMap: Record<string, any> = {
   zh: { ...zhXDataGrid },
   fa: { ...faXDataGrid },
@@ -134,8 +189,27 @@ export const useCustomTheme = () => {
     };
 
     const legacyQuery = mediaQuery as MediaQueryListLegacy;
-    legacyQuery.addListener?.(handleChange);
-    return () => legacyQuery.removeListener?.(handleChange);
+    const legacyAddListener = (
+      legacyQuery as {
+        addListener?: (
+          listener: (this: MediaQueryList, event: MediaQueryListEvent) => void,
+        ) => void;
+      }
+    ).addListener;
+    legacyAddListener?.call(legacyQuery, handleChange);
+    return () => {
+      const legacyRemoveListener = (
+        legacyQuery as {
+          removeListener?: (
+            listener: (
+              this: MediaQueryList,
+              event: MediaQueryListEvent,
+            ) => void,
+          ) => void;
+        }
+      ).removeListener;
+      legacyRemoveListener?.call(legacyQuery, handleChange);
+    };
   }, [theme_mode, setMode]);
 
   useEffect(() => {
@@ -264,6 +338,7 @@ export const useCustomTheme = () => {
           ? String(setting.background_opacity)
           : "1",
       );
+      rootEle.setAttribute("data-css-injection-root", "true");
     }
 
     let styleElement = document.querySelector("style#verge-theme");
@@ -274,6 +349,11 @@ export const useCustomTheme = () => {
     }
 
     if (styleElement) {
+      let scopedCss: string | null = null;
+      if (canUseCssScope() && setting.css_injection) {
+        scopedCss = wrapCssInjectionWithScope(setting.css_injection);
+      }
+      const effectiveInjectedCss = scopedCss ?? setting.css_injection ?? "";
       const globalStyles = `
         /* 修复滚动条样式 */
         ::-webkit-scrollbar {
@@ -323,7 +403,7 @@ export const useCustomTheme = () => {
         }
       `;
 
-      styleElement.innerHTML = (setting.css_injection || "") + globalStyles;
+      styleElement.innerHTML = effectiveInjectedCss + globalStyles;
     }
 
     const { palette } = muiTheme;