Pull Request resolves #47298 .

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

Fixes a missing space before the page class suffix in the article layout.
Previously the value of pageclass_sfx was concatenated directly with the item-page class, producing invalid class names such as item-pagepage-class.
The fix ensures the suffix is trimmed and preceded by a space when present, so CSS classes remain properly separated.

Testing Instructions

Create a Category Blog menu item.
In the Page Display tab, set Page Class to page-class.
Create an article within the same category.
Open the article via the blog menu item.
Inspect the main article container in the browser dev tools.

Actual result BEFORE applying this Pull Request

The class names are concatenated without a space:
com-content-article item-pagepage-class

Expected result AFTER applying this Pull Request

The page class suffix is correctly separated:
com-content-article item-page page-class

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed