.volver-arriba{position:fixed;right:max(18px,env(safe-area-inset-right,0px));bottom:calc(22px + env(safe-area-inset-bottom,0px));z-index:39;display:grid;place-items:center;width:48px;height:48px;padding:0;border:1px solid #111;border-radius:50%;background:#111;color:#fff;box-shadow:0 8px 24px #0002;cursor:pointer;touch-action:manipulation;animation:volver-arriba-aparece 200ms cubic-bezier(.16,1,.3,1);transition:transform 160ms cubic-bezier(.16,1,.3,1)}
.volver-arriba--con-whatsapp{bottom:calc(86px + env(safe-area-inset-bottom,0px))}
.volver-arriba svg{width:24px;height:24px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.volver-arriba[hidden]{display:none}.volver-arriba:focus-visible{outline:3px solid #303cff;outline-offset:4px}.volver-arriba:active{transform:scale(.94)}
html.sin-scroll .volver-arriba,body:has(dialog[open]) .volver-arriba{visibility:hidden;pointer-events:none}
@keyframes volver-arriba-aparece{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
@media(hover:hover) and (pointer:fine){.volver-arriba:hover{transform:translateY(-3px)}}
@media(prefers-reduced-motion:reduce){.volver-arriba{animation:none;transition:none}}