storybook/docs/_snippets/storybook-addon-css-helpers.md

import { global } from '@storybook/global';

export const clearStyles = (selector: string | string[]) => {
  const selectors = Array.isArray(selector) ? selector : [selector];
  selectors.forEach(clearStyle);
};

const clearStyle = (input: string | string[]) => {
  const selector = typeof input === 'string' ? input : input.join('');
  const element = global.document.getElementById(selector);
  if (element && element.parentElement) {
    element.parentElement.removeChild(element);
  }
};

export const addOutlineStyles = (selector: string, css: string) => {
  const existingStyle = global.document.getElementById(selector);
  if (existingStyle) {
    if (existingStyle.innerHTML !== css) {
      existingStyle.innerHTML = css;
    }
  } else {
    const style = global.document.createElement('style');
    style.setAttribute('id', selector);
    style.innerHTML = css;
    global.document.head.appendChild(style);
  }
};