these are my first times with docker, I'm trying to put the directives for MariaDB in my composer file. Once the file is written, if I try to run the docker compose up command, it gives me the following error: yaml: line 8: did not find expected key. Does anyone have the same problem as me? How can I solve? Thanks so much.

Below is my docker-compose.yaml file

version: '3'
    services:
      backend:
        build: ./
        restart: always
        volumes:
          - ./application:/var/www/html
        ports: [80:80]
       mariadb:
        image: 'bitnami/mariadb:latest'
        ports:
            - '3306:3306'
        volumes:
            - './mariadb_data:/bitnami/mariadb'
        environment:
            - ALLOW_EMPTY_PASSWORD=yes
            - MARIADB_DATABASE=db_test
            - MARIADB_USER=test_user
            - MARIADB_PASSWORD=password
            - MARIADB_ROOT_HOST='%'
    volumes:
      application:
        driver: local
      mariadb_data:
        driver: local