body {
  background-color: #0d1117;
  color: #e6edf3;
  font-family: "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}

.container {
  width: 90%;
  max-width: 700px;
  background-color: #161b22;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 0 15px rgba(0,0,0,0.5);
}

h1 {
  text-align: center;
  color: #00b4d8;
}

.subtitle {
  text-align: center;
  color: #8b949e;
  margin-bottom: 20px;
}

.chat-box {
  height: 400px;
  overflow-y: auto;
  background-color: #0d1117;
  border-radius: 10px;
  padding: 15px;
  border: 1px solid #30363d;
}

.message {
  margin: 10px 0;
  padding: 10px;
  border-radius: 10px;
  line-height: 1.4;
}

.bot {
  background-color: #21262d;
  color: #58a6ff;
}

.user {
  background-color: #238636;
  color: #fff;
  text-align: right;
}

.input-area {
  display: flex;
  margin-top: 15px;
}

#user-input {
  flex: 1;
  padding: 10px;
  border: none;
  border-radius: 10px;
  background: #21262d;
  color: #fff;
}

#send-btn {
  background: #00b4d8;
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 10px 20px;
  margin-left: 10px;
  cursor: pointer;
  transition: 0.3s;
}

#send-btn:hover {
  background: #0096c7;
}

footer {
  margin-top: 10px;
  color: #8b949e;
  font-size: 0.9em;
}