diff --git a/App/templates/error.html b/App/templates/error.html
index 5f035c9..2813469 100644
--- a/App/templates/error.html
+++ b/App/templates/error.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en">
+<html lang="en" data-bs-theme="dark">
 <head>
     <meta charset="UTF-8">
     <title>Ошибка</title>
diff --git a/App/templates/main_menu.html b/App/templates/main_menu.html
index d001b60..8fd8fc8 100644
--- a/App/templates/main_menu.html
+++ b/App/templates/main_menu.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en">
+<html lang="en" data-bs-theme="dark">
 <head>
     <meta charset="UTF-8">
     <title>Главное меню</title>
@@ -14,7 +14,7 @@
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js"></script>
 </head>
 <body class="p-3 m-0 border-0 bd-example m-0 border-0">
-  <header
+  <header>
     <div class="row flex-nowrap justify-content-between">
         <div class="col-1 pt-1"></div>
         <div class="col-10 text-center">
diff --git a/App/templates/output.html b/App/templates/output.html
index 643c6f6..224e921 100644
--- a/App/templates/output.html
+++ b/App/templates/output.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en">
+<html lang="en" data-bs-theme="dark">
 <head>
     <meta charset="UTF-8">
     <title>{{ header }}</title>
