Can you upload it here? It won't get deleted by anyone. :)

Thank you sean for reporting this great customization tool. However, I noticed that the theme only works on the page where the html is. It's normal, because the <style> tag doesn't have a scope on the whole page. 

So I found a code that allows to modify the styles of the page. So when a style initializes, it stays modified until the database is closed. It's a code in french that I found here : https://www.zonecss.fr/cours-css-javascript/acceder-aux-css-en-javascript.html

  function modifier(sChemin, sPropriete, sVal){
  var bFind = false,
      aStyleSheets = document.styleSheets,
      exp_reg =  new RegExp(sChemin,"gi");
  //console.log(aStyleSheets);
  // si la css est externe et d'un autre nom de domaine
  // cssRules: lève une DOMException: "The operation is insecure."
  // code: 18
  // message: "The operation is insecure."
  // name: "SecurityError"
  //
  for(var i = 0; i < aStyleSheets.length; ++i){
    try{
      var aCssRules =  aStyleSheets[i].cssRules;
      for(var j = 0; j < aCssRules.length; ++j){
        console.log(aCssRules[j].selectorText);
        if(exp_reg.test(aCssRules[j].selectorText)){
          aCssRules[j].style[sPropriete] = sVal;
          console.log("Trouvé", aCssRules[j].style[sPropriete]);
          bFind = true;
        }//if
      }//for
    }catch(error) {
      //cssRules: lève une DOMException: "The operation is insecure."
      //console.log(error);
      continue
    }
  }
  return bFind;
}

// expemple to modify selected tab color :
modifier('.tab.selected', 'color', 'red');

I added a CSS boy of page formula that modifies the style sheet of the web page (see the attached application)