Luma theme deconfigured after installing sample data

Console error:

Refused to apply style from 'https://app.bartofilpc.test/media/styles.css' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

After installing Magento 2 Luma theme, some front-end configuration is missing.
Commands I’ve tried:

• Copying vendorand composer.json from another project
• bin/magento setup:di:compile
• bin/magento sampledata:install and bin/magento setup:upgrade
• Removing sampledata and installing again