Question: Due to impermanance of everything, Are there anything to be happy or sad about ? Even about **dhamma** ?

If something seems like to be happy, there are some reasons to not to be happy.

1. It is impermanant for sure. but also,
2. That **happiness make sadness in the future (future includes next lives)** (I need to be sure about this sententce, please mention about this in your answer)

Are enlightened people happy ? Or neither happy nor sad ?

Answer: 
**Are there anything to care about in this universe?**

Yes, you should care about other sentient beings and practice putting their well-being foremost in your mind. If you have no experience with this, then try [practicing the four immeasurables.](https://thubtenchodron.org/meditation/03-prayers-practices/01-recitations/four-immeasurables/)

**Due to impermanance of everything, Are there anything to be happy or sad about?**

Rejoice in other's happiness! Rejoice when other's wishes come true! Rejoice in other's sorrowless bliss! Rejoice in other's progress on the path of dhamma as this is the hope of the world!

**That happiness make sadness in the future (future includes next lives)**

You've got it completely and totally wrong friend. How can happiness make sadness in this life or in the next? The problem is sentient beings don't know what happiness is or how to get it. We chase after things that *do not* lead to happiness thinking they will and we shun things that *do* lead to happiness thinking they won't. We are like a dog tied to a pole and wound round-and-round... we pull harder and harder to get free, but only succeed in binding ourselves tighter to the very thing that makes us miserable. We are quite silly and ignorant.

**Are enlightened people happy?**

Of course! They are immeasurably happy. Indescribably happy. Happy to such an extent that it is impossible to conceive. How do we know this? Because in order to become enlightened they must work for countless lifetimes at accumulating and working at the causes of happiness! They must perfect all virtuous conduct! They must perfect all virtuous minds! Take them to their zenith! Imagine a mind as wide and deep as the ocean filled with the most altruistic and peaceful thoughts. With absolutely zero ill-will and focused on other's well-being to the limit. Such a mind... we cannot even begin to describe the happiness it entails!!

**Or neither happy nor sad?**

You need to work on discovering what happiness is and the causes and conditions of happiness. Fortunately, that is exactly what the dhamma teaches. Your confusion is caused by misunderstanding. Rest assured you have it blinkered, but keep working at it and working at it and working at it... don't stop! and you'll slowly unwind that leash holding you to the pole. 

Dhamma is the Ultimate Medicine. Buddha is the Ultimate Doctor. The Sangha are the Ultimate Nurses.

The disease is dhukka and unhappiness. The cure is happiness... immeasurably so!
yes you can care about 4 ''karmas'', with the last one being the intention to get enlightened, ie not getting any birth

> 
> And of what sort, brahmin is the deed that is neither dark nor bright,
>  with a result that is neither dark nor bright, which, itself a deed,
>  conduces to the waning of deeds?
> 
> 
> In this case, brahmin the intention to abandon this dark deed with its
>  dark result, the intention to abandon this bright deed with its bright
>  result, the intention to abandon this deed both dark and bright with a
>  its result both dark and bright, - this intention is called "the deed
>  that is neither dark nor bright, with a result that is neither dark
>  nor bright, which, itself a deed, conduces to the waning of deeds."
> 
> 
> These four deeds I have myself comprehended, realized and made known."
> 
> 
> 

<https://obo.genaud.net/dhamma-vinaya/pts/an/04_fours/an04.232.wood.pts.htm#p1>