Coloring Postgresql logs in Loki according to security level

I want to capture Postgresql logs with Promtail and display them with Loki in Grafana.
I have seen many screenshots on the internet sharing that the warning info debug error logs were colored by Loki. However, I could not color them in Loki.

Although there is an error in the log below, I could not show an error in the label in the gui.

Can you guide me? Where do I need to fix or configure?
–here is config yaml for promtail

scrape_configs:
  - job_name: system
    static_configs:
      - targets:
          - localhost
        labels:
          job: express_120
          __path__: /u01/pgdata/15/data/log/*.log
    pipeline_stages:
    - multiline:
        firstline: '^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3} CET'
    - regex:
        expression: '(?P<time>^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}.\d{3}) \[(?P<level>[A-Z]+)\]? (?P<msg>(.|\n)*$)'
    - labels:
        time:
        level:
        trace:
    - timestamp:
        source: time
        format: '2006-01-02 15:04:05.000'
    - output:
        source: msg

Group by level label in your loki query, so each log level will have own timeserie in the result.

For example:
image