Littleton city leaders are ready to cast a final vote Tuesday on a proposed change to its land-use code that could spur the construction of denser housing types — like duplexes, triplexes and cottage-style homes — throughout the southern Denver suburb. But the idea isn’t going over well with many in the city of 45,000, where neighborhoods made up exclusively of detached single-family homes could become a thing of the past. “I think rezoning would take neighborhoods that have a nice country feel and quaintness to such a mixed mess that outside buyers and visitors will scratch their heads at the building plans and rules of Littleton,” said Earnest Mathis, a 34-year resident of the city.