This tutorial will guide you through the steps of adding CSS styling to a custom Drupal 10 theme.

1. Start with a Drupal 10 base theme (you’ll need to rename the theme)
2. Add a css folder to the theme’s folder

   
   # File Structure
   core
   modules
   profiles
   sites
   themes
   --contrib
   --custom
   ----d10_custom_theme_add_css
   ------css
   --------style.css
   ------d10_custom_theme_add_css.info.yml 
   ------d10_custom_theme_add_css.libraries.yml 
   

3. Add a style.css file in the css folder

   
   /**
   * @file
   * D10 custom theme global style CSS file.
   *
   * Enter any custom CSS below this comment.
   */
   
   .custom-class {
       color: fff;
   }
   

4. Add a d10_custom_theme_add_css.libraries.yml file to the theme’s folder

   
   # d10_custom_theme_add_css.libraries.yml 
   global-styling:
       css:
       theme:
           css/style.css: {}
   

5. Add the libraries: mapping scalar and sequence to the d10_custom_theme_add_css.info.yml file

   
   # d10_custom_theme_add_css.info.yml
   name: D10 Custom Theme (add css)
   type: theme
   description: 'A Drupal 10 custom theme base with custom css.'
   core_version_requirement: '^10'
   base theme: 'false'
   libraries:
       - d10_custom_theme_add_css/global-styling
   regions:
       header: 'Header'
       content: 'Content'
       sidebar_first: 'Sidebar first'
       footer: 'Footer''
   

6. Congratulations! You now have a custom theme with custom css.

More information

• Drupal: Adding assets (CSS, JS) to a Drupal theme via *.libraries.yml
• Drupal: CSS file organization
• Drupal: CSS formatting guidelines
• Drupal 10 custom theme add css repository

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.

More information

• Drupal theme folder structure
• Defining a theme with an .info.yml file
  • Required and optional items
• D10 custom theme base github repository

Thankfully, there is a module for that, but the documentation isn’t great.

1. Install the Views Node Access Filter module
2. Edit the Content view (URL: example.com/admin/structure/views/view/content, UI Path: Structure > Views > Content > Edit)
   
3. With Default display selected, click add a Filter Criteria
   
4. Check Editable and click Add and configure filter criteria
   
5. Click Apply
   
6. Save the view
   

Now the Content view will only show the user the content that they are able to edit.

You may want to check programmatically if you are on a user page or profile in Drupal 8 or 9. Use Drupal’s routeMatch to grab user. Then check if $user is an instance of user. Execute your code on that page.

$user = \Drupal::routeMatch()->getParameter('user');
if ($user instanceof \Drupal\user\UserInterface) {
  // It's a user page!
}