```js
// .storybook/preview.js

const customViewports = {
  kindleFire2: {
    name: 'Kindle Fire 2',
    styles: {
      width: '600px',
      height: '963px',
    },
  },
  kindleFireHD: {
    name: 'Kindle Fire HD',
    styles: {
      width: '533px',
      height: '801px',
    },
  },
};
```