The website encountered an unexpected error. Please try again later( Olivero subtheme) Tried to make an Olivero subtheme. Followed drupal tutorials and after several unsuccessfull attempts ended in error &quot;The website encountered an unexpected error. Please try again later&quot; on both backend and frontend now I don't get the error anymore on the backend but I still can't access the frontend.
Error in drupal log looks like this
Drupal\Core\Asset\Exception\InvalidLibraryFileException: Invalid library definition in themes/mysubtheme/mysubtheme.libraries.yml: A colon cannot be used in an unquoted mapping value at line 1 (near &quot;global-styling: version: 1.x &quot;). in Drupal\Core\Asset\LibraryDiscoveryParser-&gt;parseLibraryInfo() (line 348 of /home/admin/web/mysite.com/public_html/core/lib/Drupal/Core/Asset/LibraryDiscoveryParser.php).

mysubtheme.info.yml looks like this
type: theme
base theme: olivero
description: My custom theme based on the core Olivero theme. It's meant for customization.
package: Custom
libraries:
  - mysubtheme/css
  - mysubtheme/js

regions:
  header: Header
  primary_menu: 'Primary menu'
  secondary_menu: 'Secondary menu'
  hero: 'Hero (full width)'
  highlighted: Highlighted
  breadcrumb: Breadcrumb
  social: Social Bar
  content_above: Content Above
  content: Content
  sidebar: 'Sidebar'
  content_below: 'Content Below (Flex Layout)'
  footer_top: 'Footer Top (Flex Layout)'
  footer_bottom: 'Footer Bottom'

core: '8.x'
core_version_requirement: ^8 || ^9 

and mysubtheme.libraries.yml like this
 version: VERSION
 css:
   theme:
     css/custom.css: {}

global-scripts:
 version: VERSION
 dependencies:
   - core/jquery
   - core/drupal
   - core/drupalSettings
 js:
     js/custom.js: {}

Thank you for any help.
As @Leigh wrote in a comment one of the cause of my problem is that, sadly, OLivero doesn't support yet subtheming.