Don't. Think in terms of theming, not reinventing the wheel. Come up with a unified coherent design language, and build out themes for all of the popular exist

Don't. Think in terms of theming, not reinventing the wheel. Come up with a unified coherent design language, and build out themes for all of the popular existing libraries that anyone wants to use. Spending a sprint building a select dropdown is not something any engineer should be doing these days.