themes-wordpress/jackson/theme.json

{
    "version": 2,
    "settings": {
        "color": {
            "palette": [
                {
                    "slug": "foreground",
                    "color": "#000000",
                    "name": "Foreground",
                    "default": "#333333"
                },
                {
                    "slug": "background",
                    "color": "#ffffff",
                    "name": "Background",
                    "default": "#ffffff"
                }
            ]
        },
        "custom": {
			"color": {
				"foreground": "var(--wp--preset--color--foreground)",
				"background": "var(--wp--preset--color--background)",
				"primary": "var(--wp--preset--color--foreground)",
				"secondary": "var(--wp--preset--color--foreground)",
				"tertiary": "var(--wp--preset--color--background)"
			},
            "optOutOfParentStyleVariations": true
        }
    },
    "styles": {
        "typography": {
			"fontFamily": "var:preset|font-family|dm-sans"
        }
    }
}