Create a basic custom Drupal 10 theme tutorial

This tutorial will give you everything you need to create a very basic custom theme for Drupal 10. It will just show up as an available theme in Drupal and not much more.

  1. Create a folder named d10_custom_theme_base inside the themes/custom/ folder of your Drupal 10 installation.
    
    core
    modules
    profiles
    sites
    themes
    --contrib
    --custom
    ----d10_custom_theme_base
    
  2. Save a text file with the name d10_custom_theme_base.info.yml inside the created folder.
  3. Edit the d10_custom_theme_base.info.yml file to include the following:
    
    name: D10 Custom Theme Base
    type: theme
    description: 'A Drupal 10 custom theme base.'
    core_version_requirement: '^10'
    base theme: 'false'
    regions:
        header: 'Header'
        content: 'Content'
        sidebar_first: 'Sidebar first'
        footer: 'Footer'
    
  4. Congratulations! You have a custom theme.

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