body {font-family: Arial; margin:0; background:#f2f4f7;}
header, footer {background:#1f2d3d; color:white; text-align:center; padding:15px;}
.container {display:flex; padding:10px; gap:10px;}
.left-box,.right-box {width:20%; background:white; padding:10px;}
.middle-box {width:60%; display:flex; flex-direction:column; background:white;}
.chat-messages {flex:1; padding:10px; overflow-y:auto;}
.chat-input {display:flex; gap:10px; padding:10px;}
.message {margin-bottom:10px; padding:8px; background:#eee;}