* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Arial", sans-serif;
  background-color: #f4f4f4;
  line-height: 1.6;
}

.container {
  max-width: 800px;
  margin: 30px auto;
  padding: 20px;
}

h1 {
  text-align: center;
  margin-bottom: 20px;
  color: #333;
}

.chat-container {
  background-color: #fff;
  border-radius: 5px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  overflow: hidden;
}

.messages {
  height: 400px;
  padding: 20px;
  overflow-y: auto;
  border-bottom: 1px solid #eee;
}

.message {
  margin-bottom: 15px;
  padding: 10px;
  border-radius: 5px;
  max-width: 80%;
  word-wrap: break-word;
}

.message.sent {
  background-color: #e3f2fd;
  margin-left: auto;
}

.message.received {
  background-color: #f1f1f1;
}

.input-container {
  display: flex;
  padding: 10px;
}

#message-input {
  flex: 1;
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 4px;
  margin-right: 10px;
}

#send-button {
  padding: 10px 15px;
  background-color: #4caf50;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s;
}

#send-button:hover {
  background-color: #45a049;
}