/** * CSS class for a news category (German tag, e.g. "wm-qualifikation" → "cat-wm-qualifikation"): * every category has its own logo colour for badge and card edge (css/base.css). */ function news_cat_class(?string $sCatTag): string { $s = preg_replace('/[^a-z0-9-]/', '', strtolower((string)$sCatTag)); return $s !== '' ? 'cat-' . $s : ''; }