p <- plot_ly(
  adjusted_rates, x = ~round(expected,3), y = ~round(observed,3),
  # Hover text:
  text = ~paste("Surgeon: ", surgeon_name)
)

d <- layout(p, xaxis = x, yaxis = y,
       #plot_bgcolor=grDevices::colorRampPalette(c("red", "white", "green"))(n = 1000))
  shapes = list(
               list(type = "rect",
                    fillcolor = grDevices::colorRampPalette(c("red", "white", "green"))(n = 1000), opacity = 0.3,
                    x0 = 0, x1 = .11, xref = "x",
                    y0 = 0, y1 = .11, yref = "y")))
d