MinimalistCSS is a free and open source css framework, that allows you to make unique and modern design without writing any css.
Installation instructions can be found here.
Apart from width, height, padding and margin you can make almost everything responsive
Easy to customize everything. Bring your own style, make your own components.
Most frequently used colors on the web are already here.
User gradient colors in background, text or border.
Just import your favorite google font, and use font name as class
Make hover more interactive. Tons of styles available for hover.