/* ================= GREETING ================= */
/* RESET */
*{
  box-sizing:border-box;
}
/* BODY */
body{
  font-family:system-ui;
  margin:0;
  height:100dvh;
  overflow:hidden;
  display:flex;
  flex-direction:column;
  background:#fff;
}
/* KHUNG CHAT */
#chat-box{
  flex:1;
  overflow-y:auto;
  padding:15px;
  display:flex;
  flex-direction:column;
  gap:10px;
  padding-bottom:90px;
  -webkit-overflow-scrolling:touch;
}
/* TIN NHẮN */
.msg{
  padding:10px 14px;
  border-radius:14px;
  max-width:80%;
  font-size:15px;
  line-height:1.4;
  word-wrap:break-word;
}
.user{background:#e4f1ff; align-self:flex-end;}
.ai{background:#f2f2f2; align-self:flex-start;}
/* THANH INPUT FIX CỨNG */
#input-bar{
  position:fixed;
  bottom:0;
  left:0;
  width:100%;
  display:flex;
  padding:10px;
  border-top:1px solid #ddd;
  background:#fff;
  z-index:9999;
}
/* INPUT */
#input{
  flex:1;
  padding:10px 12px;
  font-size:16px;
  border-radius:20px;
  border:1px solid #ccc;
  outline:none;
}
/* BUTTON */
#send{
  margin-left:6px;
  padding:0 16px;
  background:#0066ff;
  color:#fff;
  border:none;
  border-radius:20px;
  cursor:pointer;
}
/* Ẩn zoom iOS khi focus */
@media screen and (max-width:768px){
  #input{font-size:16px;}
}