/* collapse css: how to use
 insert variables in :root of your main style .

template:

--hintopen: none;
--open: '- ';
--hintclosed: underline;
--closed: '+ ';

*/

.foldable{margin-bottom: 0px; text-decoration-line: var(--hintclosed)}
h2.foldable{margin-bottom: 10px}
details .foldable::before{content: var(--closed)}
details:open .foldable::before{content: var(--open)}
details:open .foldable{margin-bottom: 0.5em; text-decoration-line: var(--hintopen)}

summary{display: block}
summary .foldable{display: inlineblock}
summary{cursor: pointer}