code: function calculateNewBackgroundPosition(value) {
    const idx = value.indexOf('.')
    if (idx === -1) {
      value = `${100 - parseFloat(value)}%`
    } else {
      // Two off, one for the "%" at the end, one for the dot itself
      const len = value.length - idx - 2
      value = 100 - parseFloat(value)
      value = `${value.toFixed(len)}%`
    }
    return value
  }
docs: Takes a percentage for background position and inverts it.
  This was copied and modified from CSSJanus:
  https://github.com/cssjanus/cssjanus/blob/4245f834365f6cfb0239191a151432fb85abab23/src/cssjanus.js#L152-L175
  @param {String} value - the original value (for example 77%)
  @return {String} the result (for example 23%)