.white {
  background-color : white;
}

.black {
  background-color : black;
}

.bg_dark {
  background-color : #006699;
}

.bg_medium {
  background-color : #3399cc;
}

.bg_light {
  background-color : #66ccff;
}

.alt_bg_dark {
  background-color : #003399;
}

.alt_bg_medium {
  background-color : #3366cc;
}

.alt_bg_light {
  background-color : #6699ff;
}