details{margin:0 20px 10px;padding:0}summary.blanco::-webkit-details-marker{display:none}summary.blanco{margin:0;padding:10px;background-color:#f0f0f0;cursor:pointer;display:flex;justify-content:space-between;align-items:center;list-style:none}summary.blanco::after{content:'+';font-size:1.5em;font-weight:700;margin-right:10px;transition:transform .3s ease}details[open] summary.blanco::after{content:'×'}details>:not(summary){padding:10px}ul{margin:0}