Support Windows high-contrast mode. Fix #716
Support Windows high-contrast mode. Fix #716

kwangkim/KaTeX,azotova/KaTeX,xymostech/KaTeX,kwangkim/KaTeX,xymostech/KaTeX,xymostech/KaTeX,xymostech/KaTeX,xymostech/KaTeX,Khan/KaTeX,kwangkim/KaTeX,azotova/KaTeX,Khan/KaTeX,kwangkim/KaTeX,azotova/KaTeX,Khan/KaTeX,azotova/KaTeX,kwangkim/KaTeX,azotova/KaTeX