(function() {
  if (window.RDInjectedCSS) { return; }

  function applyStyle(doc, identifier, cssText) {
    if (!doc || !doc.head) { return; }
    var style = doc.getElementById(identifier);
    if (!style) {
      style = doc.createElement('style');
      style.id = identifier;
      doc.head.appendChild(style);
    }
    style.textContent = cssText || '';
  }

  function walkDocuments(rootDoc, includeFrames, visitor) {
    if (!rootDoc) { return; }
    visitor(rootDoc);
    if (!includeFrames || !rootDoc.querySelectorAll) { return; }
    Array.prototype.forEach.call(rootDoc.querySelectorAll('iframe'), function(frame) {
      try {
        if (!frame.contentDocument) { return; }
        walkDocuments(frame.contentDocument, includeFrames, visitor);
      } catch (error) {
      }
    });
  }

  window.RDInjectedCSS = {
    setStyle: function(identifier, cssText, options) {
      var includeFrames = !!(options && options.includeFrames);
      walkDocuments(document, includeFrames, function(doc) {
        applyStyle(doc, identifier, cssText);
      });
    },
    removeStyle: function(identifier, options) {
      var includeFrames = !!(options && options.includeFrames);
      walkDocuments(document, includeFrames, function(doc) {
        var style = doc.getElementById(identifier);
        if (style && style.parentNode) {
          style.parentNode.removeChild(style);
        }
      });
    }
  };
})();