/**
 * Elevations
 */
elevation-transition()
  merge-transition box-shadow $elevation-duration var(--transition--ease-out), background-color $elevation-duration var(--transition--ease-out)
  merge-will-change box-shadow, background-color

elevation-light($z)
  if ($z == 'inset')
    box-shadow $shadow-inset-light

  else if ($z == 0)
    box-shadow none

  else
    box-shadow $shadow-umbra-light[$z - 1], $shadow-penumbra-light[$z - 1]

elevation($z)
  if ($z == 'inset')
    box-shadow $shadow-inset-dark

  else if ($z == 0)
    box-shadow none

  else if ($z == 1)
    box-shadow $shadow-umbra-dark[0], $shadow-penumbra-dark[0]

  else
    box-shadow $shadow-umbra-dark[$z - 1], $shadow-penumbra-dark[$z - 1]