They cannot understand your colour aversion, I don't think most people can if they haven't experienced it. Think about it from their perspective, the CEO and b

They cannot understand your colour aversion, I don't think most people can if they haven't experienced it. Think about it from their perspective, the CEO and business has invested effort/money into making a decision, a decision that is not generally in your purview (design). In almost all situations, even if the CTO vetoes a design decision made by CEO, the CEO should have final say. Generally, ignoring your hypersensitivity, you cannot be upset when CEO or other teams make non-tech decisions you disagree with. Problem here is that the design impacts your work and output, which does have a business consequence. It is a business cost/risk that they did not factor into the decision. You should frame it this way, not because you have 10% and demand input in the decision because of this, this will cause your colleagues to lose trust in you. They will be worried if this issues come up when they make a non-tech decision. Separately, them not including in the design process may be a cause for concern. Is it simply that they forgot to invite you to meetings and cc you on emails? Or did they leave you out on purpose? I don't know the situation, it really could be innocent/innocous.