OnchainKit comes with first class support for tailwindcss.
1

Use default OnchainKit's style

You can use the default styles without any customization. Just place this at the top of your application’s entry point to have the components work out of the box.
import '@coinbase/onchainkit/styles.css';
2

Tailwind CSS Config

Depending on your dark mode setup, you may have to add safelist: ['dark'] to your Tailwind config.
/** @type {import('tailwindcss').Config} */
export default {
  content: ['./src/**/*.{ts,tsx}'],
  darkMode: ['class'], 
  safelist: ['dark'], 
  theme: {
    fontFamily: {
      sans: ['Inter', 'sans-serif'],
    },
  },
  plugins: [],
};
3

Toggling light / dark mode

There are many ways to handle color mode.In OnchainKit, toggling color mode works by adding / removing class name dark to the root html tag.
4

Colorscheme override

To override default colorscheme, you need to modify the following css variables:
@tailwind base;

@layer base {
  :root {
    --ock-font-family: 'your-custom-value';
    --ock-border-radius: 'your-custom-value';
    --ock-border-radius-inner: 'your-custom-value';
    --ock-text-inverse: 'your-custom-value';
    --ock-text-foreground: 'your-custom-value';
    --ock-text-foreground-muted: 'your-custom-value';
    --ock-text-error: 'your-custom-value';
    --ock-text-primary: 'your-custom-value';
    --ock-text-success: 'your-custom-value';
    --ock-text-warning: 'your-custom-value';
    --ock-text-disabled: 'your-custom-value';

    --ock-bg-default: 'your-custom-value';
    --ock-bg-default-hover: 'your-custom-value';
    --ock-bg-default-active: 'your-custom-value';
    --ock-bg-alternate: 'your-custom-value';
    --ock-bg-alternate-hover: 'your-custom-value';
    --ock-bg-alternate-active: 'your-custom-value';
    --ock-bg-inverse: 'your-custom-value';
    --ock-bg-inverse-hover: 'your-custom-value';
    --ock-bg-inverse-active: 'your-custom-value';
    --ock-bg-primary: 'your-custom-value';
    --ock-bg-primary-hover: 'your-custom-value';
    --ock-bg-primary-active: 'your-custom-value';
    --ock-bg-primary-washed: 'your-custom-value';
    --ock-bg-primary-disabled: 'your-custom-value';
    --ock-bg-secondary: 'your-custom-value';
    --ock-bg-secondary-hover: 'your-custom-value';
    --ock-bg-secondary-active: 'your-custom-value';
    --ock-bg-error: 'your-custom-value';
    --ock-bg-warning: 'your-custom-value';
    --ock-bg-success: 'your-custom-value';
    --ock-bg-default-reverse: 'your-custom-value';

    --ock-icon-color-primary: 'your-custom-value';
    --ock-icon-color-foreground: 'your-custom-value';
    --ock-icon-color-foreground-muted: 'your-custom-value';
    --ock-icon-color-inverse: 'your-custom-value';
    --ock-icon-color-error: 'your-custom-value';
    --ock-icon-color-success: 'your-custom-value';
    --ock-icon-color-warning: 'your-custom-value';

    --ock-line-primary: 'your-custom-value';
    --ock-line-default: 'your-custom-value';
    --ock-line-heavy: 'your-custom-value';
    --ock-line-inverse: 'your-custom-value';
  }
}