1. 1. Key difference: Grid System Bootstrap uses a responsive grid system that allows developers to create a layout using a 12-column grid. It provides predefined classes to specify the width of columns, making it easy to create responsive designs. Nuxt.js, on the other hand, does not have a built-in grid system but relies on CSS frameworks like Bootstrap or Tailwind CSS for layout structuring. Tailwind CSS also provides a flexible and customizable grid system but does not have predefined classes for column widths, allowing developers to have more control over the layout.

2. 2. Key difference: Component Library Bootstrap comes with a comprehensive set of ready-to-use components like buttons, forms, navigation bars, and more. These components follow a consistent design language and can be easily customized to match the overall theme of the website. Nuxt.js, being a framework, does not have a built-in component library but allows developers to easily create reusable UI components using Vue.js. Tailwind CSS provides a collection of utility classes that can be used to build custom components quickly, but it does not have a predefined set of components like Bootstrap.

3. 3. Key difference: CSS Architecture Bootstrap follows a pre-processor architecture where developers write CSS styles using Less or Sass, which are then compiled into CSS. This allows for more complex and organized stylesheets but requires additional tooling setup. Nuxt.js, being a Vue.js framework, encourages using a CSS-in-JS approach where styles are scoped to the components using the 'scoped' attribute. This can make it easier to manage the styles but may not be as flexible or powerful as a pre-processor architecture. Tailwind CSS takes a utility-first approach where developers use a large set of utility classes to style elements. This allows for rapid development and easy customization but may result in larger CSS files and limited reusability.

4. 4. Key difference: JavaScript Interactivity Bootstrap includes JavaScript plugins that provide additional interactivity to components like tooltips, modals, and carousels. These plugins can be easily integrated into a project and offer a consistent user experience. Nuxt.js, being a framework, allows developers to use any JavaScript library or plugin they prefer for interactivity. Tailwind CSS, being a UI framework, does not include any JavaScript interactivity out of the box and can be used with any JavaScript library or framework for adding interactivity.

5. 5. Key difference: Server-side Rendering Nuxt.js is a framework specifically designed for server-side rendering (SSR) and provides built-in support for pre-rendering or generating static websites. This can improve SEO, performance, and initial page load times. Bootstrap and Tailwind CSS, being CSS frameworks, do not have built-in support for SSR, but they can be used in conjunction with a framework like Nuxt.js to create server-rendered or statically generated websites.

6. 6. Key difference: Learning Curve Bootstrap has a well-documented API and a large community, which makes it relatively easier to learn and implement. Nuxt.js, being a server-side rendering framework, has a steeper learning curve as it requires knowledge of Vue.js and server-side rendering concepts. Tailwind CSS has a smaller learning curve compared to Bootstrap or Nuxt.js because of its utility-first approach and simplicity in usage.

In Summary, Bootstrap provides a responsive grid system and a comprehensive set of ready-to-use components, Nuxt.js focuses on server-side rendering and allows for easy creation of reusable UI components using Vue.js, while Tailwind CSS offers a utility-first approach for rapid development and easy customization.