// ── mb_str_pad fallback (PHP < 8.3) ──────────────────────────────
if (!function_exists('mb_str_pad')) {
    function mb_str_pad(string $str, int $length, string $pad = ' ', int $type = STR_PAD_RIGHT, string $enc = 'UTF-8'): string {
        $diff = $length - mb_strlen($str, $enc);
        if ($diff <= 0) return $str;
        $pad_unit = mb_strlen($pad, $enc);
        $pad_str  = str_repeat($pad, (int)ceil($diff / $pad_unit));
        $pad_str  = mb_substr($pad_str, 0, $diff, $enc);
        if ($type === STR_PAD_LEFT)  return $pad_str . $str;
        if ($type === STR_PAD_BOTH) {
            $left  = mb_substr($pad_str, 0, (int)floor($diff / 2), $enc);
            $right = mb_substr($pad_str, 0, (int)ceil($diff / 2),  $enc);
            return $left . $str . $right;
        }
        return $str . $pad_str;
    }
}OK