Has 咖啡色 replaced 茶色 in everyday use for "brown", or can I use both?
Their colors are similar and close. Usually, 茶色 is short of 茶叶色(color of red tea) and used for glass. For example, 茶色玻璃.  Well, 咖啡色 is usually used for other objects. Like, 咖啡色皮夹克. But it's not wrong if replace one with the other in any case.