"blueheaderbar accordionButton selected" not a "one" class name, but three. CSS selector to select an element with all three classes -
.blueheaderbar.accordionButton.selected
(note the absence of spaces!).
So, to find the input inside with jQuery, follow these steps:
var $input = jQuery(".blueheaderbar.accordionButton.selected input");
or
var $input = jQuery(".blueheaderbar.accordionButton.selected").find("input");
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