Overview of Bootstrap 4.0

Bootstrap 4.0 is a leading front-end development framework created and open-sourced by Twitter. This toolkit provides comprehensive resources for front-end developers, simplifying web design and responsive layout creation. Bootstrap 4.0 represents a significant update with new features, enhancements, and performance optimizations, offering a more modern and flexible experience compared to previous versions. The grid system in Bootstrap 4.0 has been refined, expanding from 12 to 15 columns for more precise layout control and incorporating the Flexbox layout model for easier creation of complex, responsive designs with support for vertical alignment. Components have also been notably improved, including the introduction of the Card component for flexible content display, redesigned form controls for a cleaner look and better touch device compatibility, and updates to classic components like Modals, Dropdowns, and Navbars with additional style options and interactive effects. Styling enhancements include new theme colors and improved typography with the modern Google Roboto font, as well as support for dark mode. JavaScript plugins in Bootstrap 4.0 have been restructured to be more lightweight and customizable, with a gradual shift from jQuery to native JavaScript for faster execution and reduced page load times. Bootstrap 4.0 uses Sass as a preprocessor, improving style maintainability and extensibility with features like variables, mixins, and nesting. The 'js' folder contains the source code for Bootstrap's JavaScript components and plugins, while the 'css' folder includes the core stylesheet files defining Bootstrap's foundational styles and layout rules. Bootstrap 4.0 is a powerful tool for both beginners and experienced developers, enabling the rapid creation of attractive, responsive websites and significantly boosting development efficiency while ensuring cross-device compatibility and a high-quality user experience.