substance/ui/styles/_tooltip.css

Substance is a JavaScript library for web-based content editing. It provides building blocks for realizing custom text editors and web-based publishing systems.

.sc-tooltip {
  background: #fff;
  padding: 2px 7px;
  border-radius: 3px;
  font-size: 12px;
  font-size: 12px;
  white-space: nowrap;
  box-shadow: 0 1px 2px rgba(0,0,0,0.5)
}