To change the primary color in Tailwind CSS, update your tailwind.config.js file with the custom colors you want to use:

// tailwind.config.js
module.exports = {
    theme: {
        extend: {
        colors: {
            primary: {
            50: '#f0f9ff',
            100: '#e0f2fe',
            // Add all your custom color shades here
            900: '#0c4a6e',
            }
        }
        }
    }
}

Then you can use these colors in your HTML with utility classes like bg-primary-500 or text-primary-700.