.boton-flotante-lateral{position:fixed;top:40%;right:0;z-index:9999;background:#de0606;color:#fff;padding:12px 10px;border-radius:12px 0 0 12px;text-decoration:none;writing-mode:vertical-rl;font-weight:bold;font-family:inherit;letter-spacing:1px;transition:background 0.3s;box-shadow:0 4px 16px rgba(0,0,0,0.2)}.boton-flotante-lateral:hover{background:#fe2222}.boton-flotante-lateral span{rotate:180deg}