IAd Producer and iBooks widget help

Question

Hello!
I'm trying to use iAd Producer to create a drawing widget for an iBooks project. So far, I've been able to customize the standard drawing object and it works flawlessly on the iAd Producer Preview and in Safari, but not on the iOS Simulator nor the iPad.
In the widget, there are 2 brush sizes available (small and large) and I'm trying to give visual feedback to the user, letting them know which one they selected. Initially I started with buttons but that didn't work because buttons don't have a style for on/off to let the user know that that button is selected.
I switched to radio buttons, which works great on the preview but not the actual device. Here's the code I'm using:
HTML:
<label class="brushFrame">
<input id="smallBrush" class="brush" type="radio" name="brush" value="small"><img src="assets/brush.png" />
</label>
<label class="brushFrame">
<input id="largeBrush" class="brush" type="radio" name="brush" value="large"><img src="assets/brush.png" />
</label>
CSS:
label.brushFrame > input.brush {
  display:none;
label.brushFrame > input.brush + img {
  cursor: pointer;
  width: 50%;
  height: auto;
  position: relative;
  z-index: 1;
  transition: all 0.1s ease-in-out;
label.brushFrame > input.brush:checked + img {
  opacity: 0.75 !important;
  z-index: 10 !important;
Basically, the brush should become transparent when the user selects it and because it's a radio button, it will stay transparent until the user selects the other brush. The iOS Simulator and iPad are able to render all the CSS correctly, except for when the radio button is ":checked". Background: This is my first widget and I'm very comfortable with CSS but not JavaScript.
How can I make this work?

Answer 1

Many thanks for your reply patixa. Apologies for my incorrect typing of IDs, in my iAd code they do match.
I have managed to resolve the problem as follows:
All of my iAd content was originally on the Background layer. Placing the content on Page1 has resolved the problem.
I'm not certain as to why the project worked in iAd producer preview/Safari/Widget preview but not in iBooks but no matter, switching to Page 1 solves it completely.
I notice from a few of the problems people have posted that they have a similar situation and wonder if this might be something that would help them. I've not posted replies but wonder if someone more experienced might offer a view.
Many thanks again to patixa, your kindness is greatly appreciated.