Hi,
In blocky you can see what part of the day it is, by using either the time or time in combination with sunset/sunrise from yahoo weather.
The gradual increase/decrease you can most likely do by using the “count i from to by” block.
Then you can set with how much it should increase over the defined time.
Note: I haven’t tried that block personally, but that’s how you should be able to use it.
You can also use the lux sensor to define how fast it should increase.
You can modify the “by” value using a dynamic parameter that you set using the if functions based on for instance time of day.