body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  margin: 0; padding: 0;
  display: flex;
  flex-direction: column;
  height: 600px;
}
#chat-container {
  width: 340px;
  max-width: 600px;
  margin: auto;
  background: white;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  flex: 1;
  display: flex;
  flex-direction: column;
}
#messages {
  padding: 1em;
  overflow-y: auto;
  flex: 1;
}
.msg { margin: .5em 0; }
.user { text-align: right; color: #007bff; }
.bot { text-align: left; color: #333; }
#form {
  display: flex;
  border-top: 1px solid #ddd;
}
#input {
  flex: 1;
  padding: 1em;
  border: none;
  outline: none;
}
#send {
  background: #007bff;
  color: white;
  border: none;
  padding: 1em;
  cursor: pointer;
}