。
Shouichi turned pale.
Literal
Shouichi [topic-は] deep-blue became.
Japanese uses 青 ('blue') for the color of a shocked, frightened face — where English uses 'pale' or 'white.' 真っ青 (真っ + 青) is the intensified form 'deep blue, vivid blue,' the fixed word for a blanched face. The prefix 真っ~ is the standard intensifier for colors and states: 真っ赤 ('bright red'), 真っ黒 ('pitch black'), 真っ白 ('pure white'). An interesting lexical difference in how the two languages carve up color-emotion associations.