/*
* A small utility to fix the letter kerning on macOS Chrome and Firefox when using the system font
* (San Francisco). It is now fixed in the text rendering engine in FF 58 and Chrome 64.
*/
;(() => {
  const ua = navigator.userAgent

  // macOS 10.11 (El Capitan) came with San Francisco. Previous versions used Helvetica
  const isRelevantMacOS =
    /Mac/.test(navigator.platform) &&
    (ua.match(/OS X 10[._](\d{1,2})/) || [])[1] >= 11

  // Chrome v64 and FF v58 fix the issue
  const isAffectedBrowser =
    (ua.match(/Chrome\/(\d+)\./) || [])[1] < 64 ||
    (ua.match(/Firefox\/(\d+)\./) || [])[1] < 58

  if (isRelevantMacOS && isAffectedBrowser) {
    document.documentElement.style.letterSpacing = '-0.3px'
    for (const el of document.all) {
      const fontSize = parseFloat(getComputedStyle(el).fontSize)
      if (fontSize >= 20) el.style.letterSpacing = '0.3px'
    }
  }
})()