What do these bars mean?

[Nights]

There is a HP/MP Panel widget you can turn on off. Its three bars. Red. Blue. Yellow. There's also another blue bar with a feather.

What do these all mean? No ♥♥♥♥♥♥♥ clue which is which

[ChiliOil]

Red is HP. Blue is mana. Yellow is stamina -- when it goes into negatives you lose HP. -1 is -1 hp. -2 is -2 HP, for a total of -3, -3 stam is -3 HP for a total of -6 HP vs 0 stam etc.
The feather is for feats. You gain points in that for just playing the game and i think leveling up skills.

[gimmethegepgun]

To clarify the previous point about Stamina, every time you use/lose Stamina and you have negative Stamina afterwards, you take damage equal to the amount of negative Stamina you have after the Stamina consumption. Actions that use 0 Stamina don't cause damage, no matter how negative it is.
Also, it is physical damage taken, not health lost, so things that reduce damage (not PV) or physical damage (like Opatos worship) will make you take less. It also counts as being attacked, so it will train your light or heavy armor skill (and shield if applicable, I think)

[Iyasenu]

Originally posted by gimmethegepgun:

To clarify the previous point about Stamina, every time you use/lose Stamina and you have negative Stamina afterwards, you take damage equal to the amount of negative Stamina you have after the Stamina consumption. Actions that use 0 Stamina don't cause damage, no matter how negative it is.
Also, it is physical damage taken, not health lost, so things that reduce damage (not PV) or physical damage (like Opatos worship) will make you take less. It also counts as being attacked, so it will train your light or heavy armor skill (and shield if applicable, I think)

Yep, it will train those skills, including Shield if that's your currently active combat style.
It's similar to mana overflow damage, in that respect.