These tools: bootstrap, material, etc. seem to be exactly what you need. They make sure your style is consistent and looks good without too much work. You can then configure the framework to make it look unique to your application. My impression is these frameworks are used all over the place in production, they are just customized so you might not recognize them. The last three companies I’ve worked at, one used angular material, one used bootstrap, and one had a custom css framework. The later had a tendency to build internal frameworks instead of new product and is suffering the consequences.