body{margin:0;font-family:system-ui;background:#fff}
#app{max-width:720px;margin:auto;height:100vh;display:flex;flex-direction:column}
#topbar{display:flex;justify-content:space-between;padding:12px;border-bottom:1px solid #eee}
#chat{flex:1;overflow:auto;padding:20px}
.msg{padding:12px;border-radius:12px;margin-bottom:12px;max-width:80%}
.user{background:#2563eb;color:#fff;margin-left:auto}
.res{background:#f1f5f9}
.input{display:flex;gap:10px;padding:12px;border-top:1px solid #eee}
.input input{flex:1;padding:14px;border-radius:12px;border:1px solid #ddd}
.input button{background:#2563eb;color:#fff;border:none;padding:12px;border-radius:12px}

#overlay{
display:none;position:fixed;top:0;left:0;width:100%;height:100%;
background:rgba(0,0,0,0.6);z-index:999;
}

.modal{
display:none;position:fixed;top:50%;left:50%;
transform:translate(-50%,-50%);
background:#fff;padding:20px;border-radius:12px;width:360px;z-index:1000;
}