Dark mode theme for website whit 5 rows of code

Dark mode theme

Todays website is looking very clean and solid whit white background and colorful buttons, I want to add simple and efficient way to switch light whit dark mode to prevent my eyes from burning when I`m updating my website.

Implement Bootstrap Ace Template in ASP.NET MVC 5

Good day young padawans :)
What is Bootstrap? Its a free and open-source collection of tools for creating websites and web applications. It contains HTML- and CSS-based design templates for typography, forms, buttons, navigation and other interface components, as well as optional JavaScript extensions. Developed by Twitter web devs.