* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Roboto', sans-serif;
}

body {
  background: #f0f2f5;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.chat-container {
  background: #fff;
  width: 90%;
  max-width: 400px;
  height: 520px;
  display: flex;
  flex-direction: column;
  border-radius: 15px;
  box-shadow: 0 8px 16px rgba(0,0,0,0.1);
  overflow: hidden;
}

.chat-header {
  background: #3498db;
  color: #fff;
  display: flex;
  align-items: center;
  padding: 15px;
  gap: 10px;
}

.avatar {
  width: 40px;
  height: 40px;
  background: #2980b9;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  font-size: 18px;
}

.chat-title h3 {
  font-size: 18px;
}

.chat-title span {
  font-size: 12px;
  color: #d1f7d6;
}

.chat-box {
  flex: 1;
  padding: 15px;
  overflow-y: auto;
  background: #fafafa;
}

.message {
  margin: 10px 0;
  padding: 10px;
  border-radius: 10px;
  max-width: 70%;
}

.sent {
  background: #dcf8c6;
  align-self: flex-end;
}

.received {
  background: #f1f0f0;
  align-self: flex-start;
}

.chat-input {
  padding: 10px;
  display: flex;
  gap: 10px;
  border-top: 1px solid #ddd;
  background: #fff;
}

.chat-input input {
  flex: 1;
  padding: 10px;
  border-radius: 25px;
  border: 1px solid #ccc;
  outline: none;
}

.chat-input button {
  background: #3498db;
  color: #fff;
  border: none;
  border-radius: 25px;
  padding: 10px 20px;
  cursor: pointer;
  transition: 0.3s;
}

.chat-input button:hover {
  background: #2980b9;
}
/* Mobile Responsive */
@media (max-width: 480px) {
  .chat-container {
    height: 100vh;
    border-radius: 0;
  }

  .chat-input {
    padding: 10px;
    gap: 8px;
  }

  .chat-input input {
    padding: 10px;
    font-size: 14px;
  }

  .chat-input button {
    padding: 10px 16px;
    font-size: 14px;
  }
}