takamiya rion (1st costume)
The default school uniform outfit of Nijisanji's Takamiya Rion, as seen in post #6676405.
Her default outfit consists of a white double-breasted blazer, white bow, black skirt, and white thighhighs. Her hair is tied into twintails held by red bows, while she is portrayed with red eyes (can also be purple).
This tag implicates takamiya_rion (learn more).