Underscores is a minimal, semantic starter theme designed for developers who build custom themes for content management systems. It provides a clean, well-commented codebase that serves as a foundation, eliminating the need to start from a blank file or strip down a heavy existing theme.

Key features include:

• Modern HTML5 Templates: A just-right amount of lean, semantic templates that follow current standards and are ready for customization.
• Organized Starter CSS: Smartly structured CSS in the main stylesheet helps you implement your design quickly without fighting unnecessary styles.
• Custom Template Tags and Functions: Includes separate files for template tags and helper functions to keep your template files clean and avoid code repetition.
• Responsive Navigation: A JavaScript file provides a basic toggle dropdown for menus on small screens, serving as a starting point for responsive design.
• Sample Layouts and Components: Offers practical starting points like a 404 template, optional custom header code, and two sample CSS layouts for sidebars.