I added a new page layout which inherits from the page layout 1column
:
THEME\Magento_Theme\layouts.xml
<?xml version="1.0"?>
<layout xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_layout.xsd">
<update handle="1column"/>
</layout>
THEME\Magento_Theme\page_layout\hf-grouped-product-big-1col.xml
<?xml version="1.0" encoding="UTF-8"?>
<page_layouts xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/PageLayout/etc/layouts.xsd">
<layout id="hf-grouped-product-big-1col">
<label translate="true">Hf Grouped Product (Big) -- 1 Col</label>
</layout>
</page_layouts>
If I look at the product without changing the layout to my new page layout, then it looks good:
↑ It also looks like this if I set the page layout to 1column
If I change the page layout to my new layout, then it looks like this:
Why does it look different, even though my page layout inherits 1column page layout?
I tested grouped products and simple products. It looks the same everywhere.