Custom styles from style.css not loading in frontend

Hi, looking for support with the issue, that my style.css file is not loading in the front end. When I am in the editor, the styles from style.css are visible, for example h4 should be pink as a tester. But in the frontend the file is not loading and the CSS not visible.

What has gone wrong here?
theme.json looks like this:

{
“$schema”: “https://schemas.wp.org/wp/6.5/theme.json”,
“settings”: {
“appearanceTools”: true,

    "layout": {
        "contentSize": "1000px",
        "wideSize": "1280px"
    },

    "spacing": {
        "units": [ "%", "px", "em", "rem", "vh", "vw" ]
    },
    "typography": {
        "fontFamilies": [
            {
                "fontFamily": "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif",
                "name": "System Font",
                "slug": "system-font"
            }
        ]
    },
    "useRootPaddingAwareAlignments": true
},
"templateParts": [
    {
        "area": "header",
        "name": "header"
    },
    {
        "area": "footer",
        "name": "footer"
    }
],
"version": 2

}

The file style.css is in the theme folder (no sub folders).
Thanks

Makoto

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