Halfmoon
Front-end framework with a built-in dark mode
...The framework is built entirely using CSS variables (also known as CSS custom properties). There are close to 1,500 CSS variables, which means that almost everything can be customized by overriding a property, making it very easy to theme Halfmoon to fit your brand. Learn more about customization. The components have a very standard look and feel to them, making them suitable for dashboards and tools.