Overleaf/services/web/frontend/stylesheets/components/input-suggestions.scss

.input-suggestions {
  position: relative;
}

.input-suggestions-main {
  position: absolute;
  top: 0;
  background-color: transparent;
}

.input-suggestions-shadow {
  background-color: $input-bg;
  color: var(--content-placeholder);

  & + .input-suggestions-main {
    &:focus {
      background-color: transparent;
    }
  }
}