I am searching css best practices. I mean best practices like

* {
    box-sizing: border-box;
}
body {
    font-family: Inter;   
    margin: 0;
    padding: 0;
   }
.row {
    flex-direction:row;
}

I mean something every page should contain. Can you please give me all best practices you usually use? I would like to know about html practices if you have some.

To my surprise it turned out not too easy to find them all on google.