mysticsymbolic.github.io/lib/hover-debug-helper.css

.hover-debug-helper {
  font-family: "Consolas", "Monaco", monospace;
  color: white;
  background: rgba(0, 0, 0, 0.75);
  padding: 4px;
  margin-top: 4px;
  margin-left: 4px;
}