how did the 1896 supreme court decision in plessey v. ferguson extend segregation even further than the civil rights decision of 1883

The decision of the supreme court in the year 1896 in the case of Plessey vs Ferguson upheld the laws of racial segregation for the facilities of the public but only till where the facilities which were set up separately were same in quality which also came to be known as the "separate but equal". This turned out to be a law in the United States and was said to be accepted legally.