/* Background Color */

.gray-bg {
  background: #f6f6f6;
}
.white-bg {
  background: #fff;
}
.black-bg {
  background: #222;
}
/* Color */

.white {
  color: #fff;
}
.black {
  color: #222;
}
/* black overlay */

[data-overlay] {
  position: relative;
}
[data-overlay]::before {
  background: #000 none repeat scroll 0 0;
  content: "";
  height: 100%;
  left: 0;
  position: absolute;
  top: 0;
  width: 100%;
  z-index: 1;
}
[data-overlay="3"]::before {
  opacity: 0.3;
}
[data-overlay="4"]::before {
  opacity: 0.4;
}
[data-overlay="5"]::before {
  opacity: 0.5;
}
[data-overlay="6"]::before {
  opacity: 0.6;
}
[data-overlay="7"]::before {
  opacity: 0.7;
}
[data-overlay="8"]::before {
  opacity: 0.8;
}
[data-overlay="9"]::before {
  opacity: 0.9;
}