Sattva
सत्त्व (sattva)
The strand of clarity - the light, balanced quality in which things are seen as they are.
Sattva, from sat - being - is the guna of luminosity: the quality present in a clean room, a rested mind, an honest sentence. When sattva leads, perception is accurate and action is proportionate; things weigh what they actually weigh.
The tradition prizes it but does not absolutise it. The Gita notes that even sattva binds - through attachment to happiness and knowledge. One can become subtly vain about one's own clarity, at which point it is no longer clear.
Sattva is cultivated indirectly, by inputs: food that does not agitate, media that does not inflame, company that does not perform, sleep honoured, work finished. It cannot be forced - only prepared for, the way one cleans a window rather than manufacturing the light.