.message_president{position:relative;max-height:350px;overflow:hidden;transition:max-height 1s ease}.message_president.ouvert{max-height:150vh}.message_president:not(.ouvert)::after{content:'';position:absolute;top:0;bottom:0;left:0;right:0;background:linear-gradient(rgba(255,255,255,0),rgba(255,255,255,1))}