details, summary {display: block;}
details.details_shim_closed > * {display: none;}
details.details_shim_closed > summary {display: block;}
details.details_shim_open   > summary {display: block;}
details.details_shim_closed > summary:before {display: inline-block; content: "\25b6"; padding: 0 0.1em; margin-right: 0.4em; font-size: 0.9em;}
details.details_shim_open   > summary:before {display: inline-block; content: "\25bc"; padding: 0; margin-right: 0.35em;}