Using 2012 appearance/customize

I wish to put in a page that serves a flyer for an event, but I need for it NOT to have my standard header and not to have the right sidebar appear. I use the 2012 theme. I learned that this theme does not require css code to be added. I Go to Appearance / Customize and choose hide header. This hides the header from the front (welcome) page– but not the sidebar or the top menu. I can’t find a way to specify the page I wish to alter.

I did find css code one would use on other themes that do not include this customize feature (but which also does not appear to work for the side bar or menu:
.page.page-id-456 #masthead,
.page.page-id-456 #footer-area {
display: none;
}

I altered this code to:
.page.page-id-1002 #masthead {
display: none;
}

This didn’t do anything.

Any help with this would be appreciated. Seems like it ought to be simple! ??

Thanks,
Bill

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