What is it

Flexbox is for spreading elements out into one direction (and they might wrap onto the next line).

Grid is for positioning elements into a specific grid, so two dimensions (X and Y), subgrid is up and coming and will make it easier.

Position relative or absolute allows you to force an element to change its position regardless of the flow of components around it.

Links

Suppress visited link color change:

a, a:visited, a:hover, a:active {
  color: inherit;
}

Border

Adjust Border Radius (how curved are the border corners):

borderRadius: "10px"

Expand

Remove details summary default pointer

/* firefox */
details > summary:first-of-type {
  list-style-type: none;
}

/* chrome */
::-webkit-details-marker {
  display:none;
}