Macro vs Micro layout

Using

h1 {
   writing-mode: vertical-rl;
   float: right;
}

Writing mode #

Never forget we are in writing-mode: horizontal-tb (top-bottom)

Block formating context #

Sooner or later everybody finds out the hard way that min-width default value is auto in flex items, instead of 0, like in other elements
This has major consequences when you try to style things since min-width will beat both width & max-width.
https://stackoverflow.com/questions/36247140/why-dont-flex-items-shrink-past-content-size