Integrating with exiting CSS

Integrating Tailwind CSS with an existing CSS codebase requires a deep understanding of both systems to ensure smooth compatibility and efficient utilization. Firstly, assess the existing CSS structure, identifying recurring patterns and styles that can be optimized with Tailwind's utility-first approach. For instance, if the project contains custom classes for margins, paddings, or text styles, Tailwind's utility classes can replace them, offering a more concise and maintainable solution.

CSS:

// plain css
.button {
 display: inline-block;
 padding: 10px 20px;
 font-size: 16px;
 font-weight: bold;
 text-transform: uppercase;
 border: 2px solid #333;
 background-color: #333;
 color: #fff;
 text-decoration: none;
}
.button:hover {
 background-color: #555;
 border-color: #555;
}

Before integrating with Tailwind be sure of button’s styles. 

Tailwind:

<a href="#" class="inline-block px-4 py-2 font-bold uppercase border-2 border-black bg-black text-white no-underline hover:bg-gray-800 hover:border-gray-800">Button</a>

We've replaced the existing CSS with Tailwind utility classes. The button now retains its original styles but is implemented using Tailwind's classes.