.gitgraph-tooltip {
  position: absolute;
  width: 400px;
  height: 20px;
  line-height: 20px;
  padding: 10px;
  font-size: 14px;
  text-align: center;
  color: #333;
  background: #EEE;
  border-radius: 5px;
  margin-left: 25px;
  margin-top: -15px;
}
.gitgraph-tooltip:after {
  content:"";
  position: absolute;
  width: 0;
  height: 0;
  border-width: 10px;
  border-style: solid;
  border-color: transparent #EEEEEE transparent transparent;
  top: 10px;
  left: -20px;
}
.gitgraph-tooltip {
  position: absolute;
  margin-top: -15px;
  margin-left: 25px;
  padding: 10px;
  border-radius: 5px;
  background: #EEE;
  color: #333;
  text-align: center;
  font-size: 14px;
  line-height: 20px;
}

.gitgraph-tooltip:after {
  position: absolute;
  top: 10px;
  left: -20px;
  width: 0;
  height: 0;
  border-width: 10px;
  border-style: solid;
  border-color: transparent;
  border-right-color: #EEE;
  content: "";
}

Refactor and reorganize the CSS a bit
Refactor and reorganize the CSS a bit
