.group { padding: 5 px; background:lightgray; border: dotted gray 2px }

a.grouplink { font-size:larger; font-weight:bolder }

.smallpad { padding: 5 px; backgroup:yellow }

.prior,
#show,
#hide:target {
	display: none;
}

#hide:target + #show,
#hide:target ~ .prior {
	display: inline;
}