How to use the gatsby-design-tokens.colors.text function in gatsby-design-tokens

neutral: c.grey[50],
    neutralLight: c.grey[30],
    background: c.white,
    accent: c.yellow[60],
    light: c.purple[10],
    lightActive: c.purple[20],
  },
  input: {
    background: c.white,
    backgroundFocus: c.white,
    border: c.grey[30],
    focusBorder: c.white,
    focusBoxShadow: c.purple[60],
    icon: c.grey[50],
    iconFocus: c.grey[60],
    placeholder: c.text.placeholder,
  },
  // new tokens
  card: {
    background: c.white,
    color: c.grey[50],
    header: c.black,
    starterLabelBackground: c.teal[5],
    starterLabelText: c.teal[70],
    pluginLabelBackground: c.orange[5],
    pluginLabelText: c.orange[90],
  },
  modal: {
    background: c.white,
    overlayBackground: hex2rgba(c.white, 0.95),
  },
  navigation: {

background: c.white,
  // Primary brand color for links, buttons, etc.
  primary: c.gatsby,
  // A secondary brand color for alternative styling
  secondary: c.purple[40],
  // A contrast color for emphasizing UI
  accent: c.orange[60],
  // A faint color for backgrounds, borders, and accents that do not require high contrast with the background color
  muted: c.grey[5],
  // end Theme-UI required keys
  banner: c.purple[70],
  // gatsby-design-tokens has the following in colors.text,
  // which conflicts with theme-ui's default color `text`
  // making text.header and text.secondary available as
  // `heading` and `textMuted` resolves that
  heading: c.text.header, // text.header
  textMuted: c.text.secondary, // text.secondary
  // moved `text.placeholder` to `input.placeholder`
  // ref. e.g. https://github.com/system-ui/theme-ui/blob/702c43e804046a94389e7a12a8bba4c4f436b14e/packages/presets/src/tailwind.js#L6
  // transparent: `transparent`,
  // expand `gatsby-design-tokens` defaults
  code: {
    ...c.code,
    // refactor names
    background: c.code.bg,
    backgroundInline: c.code.bgInline,
    // modify token color values to comply to WCAG 2.0 AA standard contrast ratios
    // changed
    selector: `#b94185`,
    keyword: `#096fb3`,
    comment: `#527713`,
    tag: `#137886`,