CSS variables in `styled-components`

global-styles.js

import {createGlobalStyle} from 'styled-components';

// This becomes the source of truth for the application
export default const GlobalStyle = createGlobalStyle`
  :root {
    --primary: cyan;
    --text: #506784;
    --borders: #EBF0F8;
    --page-background: transparent;
    --nav-background: white;
    /* add more colors */

    --font-primary: "Helvetica Neue", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: "SFMono-Regular",  Consolas,  "Liberation Mono",  Menlo,  Courier,  monospace;

    --x1: 4px;
    --x2: 8px;
    --x3: 16px;
    --x4: 24px;
    --x5: 32px;
    --x6: 64px;

    --f1: 0.75rem;
    --f2: 0.875rem;
    --f3: 1rem;
    --f4: 1.25rem;
    --f5: 1.5rem;
    --f6: 2rem;

    /* add more variables to fill our your system */
  }
`