Template:Cars/styles.css

.cars-nav.simple-navbox .simple-list {
  border-top: 1px solid #ddf; 
  border-bottom: 1px solid #88b !important;
  border-left: 1px solid #ddf; 
  border-right: 1px solid #88b;
  padding: 2px;
  text-align: center;
}
.cars-nav.simple-navbox .simple-group {
  text-align: center;
  vertical-align: middle;
}
.cars-nav.simple-navbox .simple-group::after {
  content: "";
}