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;
}