At 15th level, your ability to move between planes enables you to slip through the planar boundaries to lessen the harm done to you during battle. When you take damage from an attack, you can use your reaction to give yourself resistance to all of that attack's damage on this turn.
Say an enemy attacks a Horizon Walker ranger with a flame tongue longsword and uses Divine Smite, giving the attack 3 different damage types.
If the ranger uses their reaction to use Spectral Defense, does that mean that for the rest of that turn, they have resistance to all 3 types of damage? If the enemy tries to do the same thing again, does the ranger still have resistance, since it says for the turn?