Fresh install, CI_DEVELOPMENT in .env not work

Dear all, i have just fresh install of Codeigniter from composer. After installation, i go to env, rename it to .env and uncomment CI_ENVIRONMENT = development.
But when i do "php spark serve" from terminal, it open localhost:8080 with "Page rendered in 0.0455 seconds Environment: production" in it footer page. Look like changing configuration in .env doesn't work anymore.
Is there anysolution? Thanks.
Look Page rendered in 0.0455 seconds

Environment: production
Page rendered in 0.0455 seconds

Environment: production