Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.7)
// Compass (v1.0.1)
// ----

$z-layers: (
  "goku":            901, 
  "shoryuken":       800,
  "modal": (
    "base":           500,
    "close":          100,
    "header":          50,
    "footer":          10
  ),
  "default":            1,
  "below":             -1
);
@function map-deep-get($map, $keys...) {
  @each $key in $keys {
    $map: map-get($map, $key);
  }
  @return $map;
}
.close {
  z-index: map-deep-get($z-layers, 'modal', 'close');
}

SassMeister-output.css

.close {
  z-index: 100;
}