What are Maycomb's rules?(including those that are unspoken)

Atticus specialized in the law. This particular case had a heavy unwritten social component to it. Racism in the white South was ingrained in people of Maycomb. Although slavery had been abolished, there was still segregation. Social "norms" were written in stone and, although not laws, carried heavy unwritten penalties for breaking. People were expected to go to church. Tom Robinson felt sorry for a white girl. He went into her house/shack and tried to help her. This was an unwritten social rule. Blacks do not mix with whites, especially young black men and white women. In Atticus' summation, he says that Tom Robinson's only crime was the fact that he had the “unmitigated temerity to feel sorry for a white woman”. For this the man was put on trial and accused of rape. Everybody knew the truth, but the word of a white girl, even Mayella Ewell's, held greater weight in the eyes of the jury.