The whole habitable band β the bit with air you can breathe and ground you can stand on β is a few kilometres thick on a planet 12,742 km across. Drag the probe through the column and watch what happens to temperature, pressure and density. Every number is computed live from the standard models.
Air molecules scatter short wavelengths far more strongly than long ones β the strength goes as 1/Ξ»β΄, so blue light is scattered about 5.5 times more than red. Overhead, sunlight passes through a short slice of atmosphere and you see that scattered blue. Near the horizon the path is up to 38 times longer, so the blue is scattered away entirely before it reaches you and only red and orange survive.