@waifu simple mostly non intrusive css library
if you just add the css to you page it won't do much
but it has a buuuunch of classes
like <button class="button">
or <p class="title">
and it has modifiers for colors, size and stuff
so you can do <button class="button is-large is-info"> which will make a big blue button (you can customize the colors, info is blue by default)
https://bulma.io/documentation/start/syntax/

they have "elements" which are simple single class modifiers and "components" which allow you to make more complex things
https://bulma.io/documentation/elements/
https://bulma.io/documentation/components/

its super easy to use
you still need some of your own css to complement but 99% of what i do, bulma handles