@chatui/core/es/components/Backdrop/style.less

The React library for Chatbot UI

.Backdrop {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: @zindex-backdrop;
  transition: 0.3s;
  width: 100vw;
  height: 100vh;
  background: var(--color-mask);
  opacity: 0;
  outline: 0;

  &.active {
    opacity: 1;
  }
}