fixed start page and scroll in modal window

src/components/landing/Navbar.jsx

@@ -1,16 +1,23 @@
 import { useTranslation } from 'react-i18next';
 import GlobeIcon from "../icons/GlobeIcon";
+import MoonIcon from "../icons/MoonIcon";
+import SunIcon from "../icons/SunIcon";
 import { useLanguageToggle } from "../../hooks/useLanguageToggle";
+import { useTheme } from "../../context/ThemeContext";
 
 export default function Navbar({ onLoginClick }) {
   const { t } = useTranslation();
   const { language, toggleLanguage } = useLanguageToggle();
+  const { theme, toggle: toggleTheme } = useTheme();
 
   return (
       <nav className="nk-nav">
         <span className="nk-logo">{t('app.name')}</span>
 
         <div className="nk-nav-right">
+          <button className="nk-theme-btn" onClick={toggleTheme} title={theme === 'dark' ? t('sidebar.lightTheme') : t('sidebar.darkTheme')}>
+            {theme === 'dark' ? <SunIcon /> : <MoonIcon />}
+          </button>
           <button className="nk-lang-btn" onClick={toggleLanguage}>
             <GlobeIcon />
             {language === 'ru' ? 'EN' : 'RU'}