Simple miniature UI (almost) classless CSS "framework". It includes normalize.css reset and really basic flex based responsive grid system.
See exmple here: https://vojtaklos.gitlab.io/classless-css/
When I am building some quick mockup or just experimenting or just making something that does not need to be designed but I want it to look at least relatively good I always needed to include Bootstrap or something similar (I know there are much smaller libraries, read onwards). With this type of framework there is almost unlimited posibilities and although I know Bootstrap really well, I sometimes do not feel like adding classes to everything and want to focus on simply writing the interesting part and leaving the boring part that i already wrote a thousand times (CSS Framework classes). Thus I created classless.css.
I mean you write HTML tags without classes and it looks good! Seriously. It is easily customizable because you can just add a class to any element and overwrite the default values.
Yes we have 4 classes. is-valid and is-error for form inputs and then container and grid for the grid system.
is-valid and is-error give green/red border to form inputs.
container class is there to restrict and center width of the webpage.
grid sets up a flex container and if you put divs inside they will act like columns and will have basic responsivness for mobile devices.