/* Root page stays still; only the conversation scrolls. */
body.chat-active{position:fixed;inset:0;width:100%;height:100%;overflow:hidden;overscroll-behavior:none}
body.chat-active .app{position:fixed;top:var(--chat-top,0px);left:0;right:0;bottom:auto;width:100%;height:var(--chat-height,100dvh);margin:0 auto;overflow:hidden}
.chat-active #conversation{min-height:0;flex:1 1 0;overscroll-behavior:contain}
.chat-active #footer{flex:0 0 auto}