Specify a color in a contour plot according to density?

The following code allows one to manipulate the parameters and see the corresponding contours for a bivariate normal. What I would like to
do is make the background white after the density is below a value say .02. Using the following code creates a dark blue background. I was wondering
if is blue because the density is less a particular value but am not sure. Is this possible to specify a density value, below which you can specify a color?
I played around with ContourShading but with no success. Here is my code:

Manipulate[
 ContourPlot[
  PDF[BinormalDistribution[{Subscript[\[Mu], 1], Subscript[\[Mu], 
     2]}, {Subscript[\[Sigma], 1], Subscript[\[Sigma], 
     2]}, \[Rho]], {x, y}], {x, -3, 3}, {y, -3, 3}, 
  ContourLabels -> True, PlotRange -> All, 
  PlotPoints -> 40], {Subscript[\[Mu], 1], -2, 2}, {Subscript[\[Mu], 
  2], -2, 2}, {Subscript[\[Sigma], 1], 1, 3}, {Subscript[\[Sigma], 2],
   1, 3}, {\[Rho], -0.9, 0.9}]

You may play around with PlotLegends and ColorFunction. For example

Manipulate[
 ContourPlot[
  PDF[BinormalDistribution[{Subscript[\[Mu], 1], 
     Subscript[\[Mu], 2]}, {Subscript[\[Sigma], 1], 
     Subscript[\[Sigma], 2]}, \[Rho]], {x, y}], {x, -3, 3}, {y, -3, 
   3}, ContourLabels -> True, PlotRange -> All, PlotPoints -> 40, 
  PlotLegends -> Automatic, 
  ColorFunction -> (ColorData["GreenBrownTerrain"][
      1 - #] &)], {Subscript[\[Mu], 1], -2, 
  2}, {Subscript[\[Mu], 2], -2, 2}, {Subscript[\[Sigma], 1], 1, 
  3}, {Subscript[\[Sigma], 2], 1, 3}, {\[Rho], -0.9, 0.9}]

Gianluca,
Your suggestion is very helpful and what I was looking for. I have a couple of follow-up questions.
Did you create the GreenBrownTerrain? Could you send me where to look to create other color profiles?
Thanks for all your help!
Terry

Terry,

You can find the gradients listed here: Color Schemes—Wolfram Documentation

It’s one of the thousands of features of Mathematica. Look up ColorData, ColorSchemes in the documentation. There is also a ColorSchemes palette.