Background blend http://codepen.io/mbonaci/pen/BNNxER

style.scss

$transp: rgba(255,255,255,0);

$colors: 
  lighten(steelblue, 20%),
  lightblue,
  skyblue,
  steelblue, 
  darken(steelblue, 10%),  
  darken(steelblue, 10%),
  darken(steelblue, 10%),
  lighten(steelblue, 20%),
  darken(steelblue, 10%),
  darken(steelblue, 10%),
  darken(steelblue, 10%),
  darken(steelblue, 1%),
  lighten(steelblue, 20%);

$warm: (
  colors: $colors,
  bg-color: white
);

@function gradient($colors, $direct: 60deg) {
  
  $out: null;
  
  @for $item from 1 through length($colors) {
    $color: nth($colors, $item);
    $pos: percentage($item/length($colors)/2);
    
    $out-string: $color #{$pos - 10}, $color #{$pos};
    $out: append($out, $out-string, comma);
  }
  
  @for $item from 1 through length($colors) {
    $color: nth($colors, $item);
    $pos: percentage($item/length($colors)/2) + 50;
    
    $out-string: $color #{$pos - 10}, $color #{$pos};
    $out: append($out, $out-string, comma);
  }
  
  @return linear-gradient($direct, $out);
}

@mixin gradient-set ($colors-set: $cold,$direct: 60deg, $size: 6){
  $grad-colors: map-get($colors-set, colors);
  $bg-color: map-get($colors-set, bg-color);

  background-image: gradient($grad-colors,$direct),
    gradient($grad-colors, $direct: -$direct);
  background-color: $bg-color;
  background-size: #{$size}em #{$size*1.72}em;
  }



HTML, BODY {
  height: 100%;
}

BODY {
  @include gradient-set($warm, 60deg, 6);
  background-blend-mode: multiply, normal;
  }