From Mobile to PC: Implementation Steps of Responsive Layout with Bootstrap 5

Bootstrap 5 is an efficient tool for implementing responsive web layouts, with core advantages including automatic adaptation to multi-device responsive design, a 12-column grid system, rich components, and a lightweight CDN introduction method. When using it, CSS and JS files must first be introduced via CDN in HTML, and the key is to set the `<meta name="viewport">` tag to ensure correct display on mobile devices. Its responsive core lies in the grid system: the page is divided into 12 columns, content is wrapped with `row`, and `col-*` specifies the column width (`*` is the number of columns). Breakpoint prefixes (xs < 576px, sm ≥ 576px, md ≥ 768px, lg ≥ 992px, xl ≥ 1200px) are used to adapt to different screens. Containers are divided into fixed-width `container` and full-screen `container-fluid`. In practice, the grid system can quickly achieve adaptive layouts for content areas and sidebars (e.g., `col-lg-9` for content area and `col-lg-3` for sidebar, which automatically stack into `col-sm-12` on small screens). Utility classes like `text-center` and `bg-*` can optimize styles. Mastering these core points allows pages to be displayed properly on mobile phones, tablets