injectTheme fix

Resources/landing-page/js/scripts.js

@@ -79,12 +79,13 @@ function injectTheme(theme,container="head") {
     if (container === "head") {
         html_element = document.head;
     } else html_element = document.body;
-    let link = document.createElement("link");
+    let themeOption = document.getElementById("theme-option")
+    let link = themeOption ? themeOption : document.createElement("link");
     url = "/CSS/variables/"
     link.type = "text/css";
     link.rel = "stylesheet";
     link.href = `${url}/${theme.toLowerCase()}.css`;
-  
+    link.id = `theme-option`
     html_element.appendChild(link);
   }