"Takaaa-chan, I can't see you~~" "You can't see because you're blindfolded."
Literal
Taka-chan see-don't [drawn-out-な~い~]. / Blindfold do-[are-してる] [because-んだから] natural is.
A child's game. 見えな~い~ stretches the vowels of 見えない into a sing-song complaint — written style for drawn-out tone. 目隠しする ('to do a blindfold / cover one's eyes') is the fixed verb. んだから is the explanatory ~んだから, presenting a reason the listener should already know — so の + だから = 'it's because X (as you know).' 当然だ ('of course, naturally') is the sharp retort.