style.css

@import "node_modules/ol/ol.css";

.map {
  width: 100%;
  height: 400px;
}
.ol-tooltip {
  position: relative;
  background: rgba(0, 0, 0, 0.5);
  border-radius: 4px;
  color: white;
  padding: 4px 8px;
  opacity: 0.7;
  white-space: nowrap;
  font-size: 12px;
  cursor: default;
  user-select: none;
}
.ol-tooltip-measure {
  opacity: 1;
  font-weight: bold;
}
.ol-tooltip-static {
  background-color: #ffcc33;
  color: black;
  border: 1px solid white;
}
.ol-tooltip-measure:before,
.ol-tooltip-static:before {
  border-top: 6px solid rgba(0, 0, 0, 0.5);
  border-right: 6px solid transparent;
  border-left: 6px solid transparent;
  content: '';
  position: absolute;
  bottom: -6px;
  margin-left: -7px;
  left: 50%;
}
.ol-tooltip-static:before {
  border-top-color: #ffcc33;
}

.center {
  margin: auto;
  width: 30%;
  padding: 10px;
}