Currently, the Night Light Mode mode knobValue goes from the variable (minimum value) to the variable (maximum value).

In the definition of getOnTimeUsingKnob:

1. Declare a const float variable named scaledKnobValue and assign it to be the difference between knobValue and the nightLightMinValue with the statement
2. Replace the value of knobRatio with the ratio of scaledKnobValue to nightLightRange so that the statement is now
3. Test your code and notice that the brightness drops to 0 when entering nightLightMode.
4. Fix this problem by inverting the knobRatio by adding the statement knobRatio = 1 - knobRatio;