diff --git a/telethon_generator/data/html/core.html b/telethon_generator/data/html/core.html
index 7d1dfc73..aed00864 100644
--- a/telethon_generator/data/html/core.html
+++ b/telethon_generator/data/html/core.html
@@ -11,7 +11,7 @@
 
             // setTheme(<link />, 'light' / 'dark')
             function setTheme(theme) {
-                document.cookie = 'css=' + theme + '; path=/';
+                localStorage.setItem('theme', theme);
                 return style.href = 'css/docs.' + theme + '.css';
             }
 
@@ -24,9 +24,7 @@
                 });
             }
 
-            setTheme(document.cookie
-                .split(';')[0]
-                .split('=')[1] || 'light');
+            setTheme(localStorage.getItem('theme') || 'light');
 
             document.addEventListener('DOMContentLoaded', function () {
                 setThemeOnClick('light', document.getElementById('themeLight'));
diff --git a/telethon_generator/docswriter.py b/telethon_generator/docswriter.py
index 1e248341..4b0929bd 100644
--- a/telethon_generator/docswriter.py
+++ b/telethon_generator/docswriter.py
@@ -45,7 +45,7 @@ class DocsWriter:
     <link id="style" href="{rel_css}/docs.{def_css}.css" rel="stylesheet">
     <script>
     document.getElementById("style").href = "{rel_css}/docs."
-        + (document.cookie.split(";")[0].split("=")[1] || "{def_css}")
+        + (localStorage.getItem("theme") || "{def_css}")
         + ".css";
     </script>
     <link href="https://fonts.googleapis.com/css?family=Nunito|Source+Code+Pro"