* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background: #000000;
  color: #FFFFFF;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
#app { width: 100%; max-width: 480px; padding: 24px; }
.brand { text-align: center; margin-bottom: 32px; }
.brand h1 { font-size: 28px; font-weight: 700; color: #FFFFFF; }
.tagline { font-size: 13px; color: #4A90D9; margin-top: 4px; }
.login-form { display: flex; flex-direction: column; gap: 12px; }
.login-form input {
  background: #111111;
  border: 1px solid #333333;
  border-radius: 6px;
  color: #FFFFFF;
  font-size: 15px;
  padding: 12px 16px;
  outline: none;
}
.login-form input:focus { border-color: #4A90D9; }
.login-form button {
  background: #4A90D9;
  border: none;
  border-radius: 6px;
  color: #FFFFFF;
  cursor: pointer;
  font-size: 15px;
  font-weight: 600;
  padding: 12px;
}
.login-form button:hover { background: #2B6CB0; }
.error { color: #FF4444; font-size: 13px; text-align: center; }
.hidden { display: none !important; }
#chat-screen {
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-width: 100%;
  padding: 0;
}
.chat-header {
  align-items: center;
  background: #111111;
  border-bottom: 1px solid #222222;
  display: flex;
  gap: 10px;
  padding: 12px 16px;
}
.chat-header span { flex: 1; font-weight: 600; }
#logout-btn {
  background: none;
  border: 1px solid #333333;
  border-radius: 4px;
  color: #AAAAAA;
  cursor: pointer;
  font-size: 12px;
  padding: 4px 10px;
}
#messages {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.message {
  max-width: 80%;
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 14px;
  line-height: 1.5;
}
.message.user {
  align-self: flex-end;
  background: #4A90D9;
  color: #FFFFFF;
}
.message.assistant {
  align-self: flex-start;
  background: #1A1A1A;
  color: #FFFFFF;
  border: 1px solid #333333;
}
.message.system {
  align-self: center;
  color: #666666;
  font-size: 12px;
  font-style: italic;
}
.chat-input {
  border-top: 1px solid #222222;
  display: flex;
  gap: 8px;
  padding: 12px 16px;
}
.chat-input input {
  background: #111111;
  border: 1px solid #333333;
  border-radius: 6px;
  color: #FFFFFF;
  flex: 1;
  font-size: 14px;
  outline: none;
  padding: 10px 14px;
}
.chat-input input:focus { border-color: #4A90D9; }
.chat-input button {
  background: #4A90D9;
  border: none;
  border-radius: 6px;
  color: #FFFFFF;
  cursor: pointer;
  font-weight: 600;
  padding: 10px 18px;
}
.chat-input button:hover { background: #2B6CB0; }
.chat-input button:disabled { background: #333333; cursor: not-allowed; }
.footer { color: #444444; font-size: 11px; padding: 8px 16px; text-align: center; }
.footer a { color: #4A90D9; text-decoration: none; }