I have a custom theme, extends the luma theme, everything works properly. My custom less modifications were added in web/css/source/_extend.less

Now I would like to create a subtheme from this custom theme I created previously, but if I add a content to /web/css/source/_extend.less the css modifications added in the parent theme are not taken in consideration.

Shouldn't they be merged or how can i add elegantly new modifications to this new subtheme without copying over again the ones from the previous one. (I understand that _theme.less is not merged but from what I read _extend.less should be merged)

Can anyone help me?


1 Answer 1


This is not a bug and seems to be the expected behaviour, here you can find some workarounds https://github.com/magento/magento2/issues/8852

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