mainCol

In web development, `mainCol` is a term commonly associated with the semantic structure of web pages, particularly in the context of HTML5 and responsive design. While not a standard HTML element, `mainCol` often refers to the primary content column within a layout, typically containing the main content of a webpage. This concept is closely related to the `<main>` element in HTML5, which is used to define the dominant content of a document, excluding secondary content like sidebars or navigation.

The use of `mainCol` in frameworks or design systems (such as Bootstrap or custom CSS grids) may refer to a predefined class or utility for styling a column that holds the primary content. For example, in responsive layouts, a `mainCol` might expand to full width on mobile devices but shrink to a specific width (e.g., 80% or 60%) on larger screens, allowing space for a secondary column like a sidebar. This approach ensures content remains accessible and readable across different devices.

Developers may implement `mainCol` using CSS Flexbox, Grid, or utility-first frameworks. For instance, in a CSS Grid layout, a `mainCol` could be defined with a fixed or flexible width, while adjacent columns (e.g., for navigation or ads) would occupy the remaining space. The exact implementation depends on design requirements, but the goal is to maintain clarity and usability.

While not a formal HTML attribute, `mainCol` serves as a practical shorthand in documentation or code comments to describe the role of a content-bearing column. Its usage reflects broader trends in modular, component-based web design, where reusable elements improve maintainability and consistency.