menu.html

<div id="mySidenav" class="sidenav">
<div>
<script>
function redirigir() {
  var selector = document.getElementById('selector-idioma');
  var url = selector.value;
  window.location.href = url;
}
</script>
<select id="selector-idioma" onchange="redirigir()">
  <option value="">Select</option>
  <option value="https://grouvex.github.io/es/grouvex">Español</option>
  <option value="https://grouvex.github.io/en/grouvex">English</option>
  <option value="https://grouvex.github.io/fr/grouvex" disabled>Français</option>
  <!-- Añade más opciones de idioma según sea necesario -->
</select>
  <script src="../index.js"></script>
<span class="status new">New</span>
<select id="themeSelect">
  <option value="default">Default Theme</option>
  <option value="theme1">Theme 1: Color</option>
  <option value="theme2">Theme 2: Color</option>
  <option value="space" >Theme Space</option>
  <option value="starwars" class="hiddenOption">Theme Star Wars</option>
  <option value="jurassicworld" class="hiddenOption">Theme Jurassic World</option>
  <option value="taylorswift" class="hiddenOption">Theme Taylor Swift</option>
  <!-- Añade tantas opciones como diseños tengas -->
</select>
<style>
  .hiddenOption {
    display: none;
  }
</style>
</div>
 <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <span><img src="../img/GROUVEX.png" alt="Grouvex" class="red1"></span>
  <span><a href="https://grouvex.github.io" class="menuT">Inicio</a></span>
  <span><img src="../img/Instagram.png" alt="Instagram" class="red1"></span>
  <span><a href="ig" class="menuT">Instagram</a></span>
  <span><img src="../img/YouTube.png" alt="YouTube" class="red1"></span>
  <span><a href="yt" class="menuT">YouTube</a></span>
  <span><img src="../img/TikTok.png" alt="TikTok" class="red1"></span>
  <span><a href="tt" class="menuT">TikTok</a></span>
  <span><img src="../img/Spotify.png" alt="Spotify" class="red1"></span>
  <span><a href="sp" class="menuT">Spotify</a></span>
</div>