body {
  font-family: sans-serif;
  background: #f4f4f4;
}
.login-box, .chat-container {
  width: 100%;
  max-width: 500px;
  margin: 50px auto;
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
}
#chat-box {
  height: 400px;
  overflow-y: auto;
  border: 1px solid #ccc;
  padding: 10px;
  margin-bottom: 10px;
  background: #fafafa;
}
.chat-img {
  max-width: 200px;
  margin-top: 5px;
}
form {
  display: flex;
  gap: 10px;
}
input[type=text] {
  flex: 1;
  padding: 8px;
}