To edit the “Add To Cart” popup that appears when you add an item to a cart in Virtuemart, there are few files that you need to know about. These are the files to know \components\com_virtuemart\themes\default\theme.js \components\com_virtuemart\js\mootools\ - contains the files for editing the appearance of the popup. To edit the appearance of the box, edit \components\com_virtuemart\js\mootools\mooPrompt.css to change the styles as well as editing the 2 images in the directory to edit how they appear as well (close box and header-background)
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