.container-fluid, .row {
  margin:0;
  padding:0;
}

.arrow_down, .arrow_top {
  position:relative;
}

.arrow_down:before {
  position:absolute;
  width:49%;
  left:0;
  bottom:0;
  border-bottom:20px solid white;
  border-right:20px solid transparent;
  display:block;
  content:" ";
}

.arrow_down:after {
  position:absolute;
  left:49%;
  bottom:0;
  right:0;
  border-bottom:20px solid white;
  border-left:20px solid transparent;
  display:block;
  content:" ";
}

.arrow_top:before {
  position:absolute;
  width:49%;
  left:0;
  top:0;
  border-top:20px solid white;
  border-right:20px solid transparent;
  display:block;
  content:" ";
}

.arrow_top:after {
  position:absolute;
  left:49%;
  top:0;
  right:0;
  border-top:20px solid white;
  border-left:20px solid transparent;
  display:block;
  content:" ";
}