.d3-tip {
  white-space:nowrap;
  line-height:1;
  font-size:12px;
  display:none;
  padding:12px;
  background:rgba(0,0,0,.8);
  color:#fff;
  border-radius:4px;
  border-color:#000;
  pointer-events:none;
  z-index: 2;
}

@media screen and (min-width:800px) {
  .d3-tip{ display:block }
}

.d3-tip:after{ 
  box-sizing:border-box;
  display:none;
  font-size:10px;
  width:100%;
  line-height:1;
  color:rgba(0,0,0,.8);
  position:absolute;
  pointer-events:none
}

@media screen and (min-width:800px) {
  .d3-tip:after{ display:inline }
}

.d3-tip.n {
  margin:-10px 0 0;
}
.d3-tip.n:after {
  content:"\25BC";
  margin:-3px 0 0;
  top:100%;
  left:0;
  text-align:center
}

.d3-tip.ne {
  margin: -10px 0 0 -45px;
}
.d3-tip.ne:after {
  content:"\25BC";
  bottom: -8px;
  left: 18px;
  text-align:left;
}

.d3-tip.nw {
  margin: -10px 0 0 45px;
}
.d3-tip.nw:after {
  content:"\25BC";
  bottom: -8px;
  right: 18px;
  text-align: right;
}