How can I override phtml, XML and CSS files that are overridden or created in custom theme.
You can achieve this via creating a new child theme.
suppose this is your current theme:
Copy your current theme in same directory like below:
Now you have to update your code in theme.xml
It should like:
<!-- /** * Copyright © 2016 Magento. All rights reserved. * See COPYING.txt for license details. */ --> <theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd"> <title>Custom child theme</title> <parent>your_parent_namespace/your_parent_theme</parent> <media> <preview_image>media/preview.jpg</preview_image> </media> </theme>
Make sure you have to give your current theme name as a parent in newly created child theme.