:root {
  font-family: Arial, sans-serif;
  color: #102a43;
  background: #f4f7fb;
}

body {
  margin: 0;
  padding: 24px;
}

.app {
  max-width: 720px;
  margin: 0 auto;
  background: #ffffff;
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 8px 24px rgba(16, 42, 67, 0.12);
}

h1 {
  margin-top: 0;
  margin-bottom: 8px;
}

.subtitle {
  margin-top: 0;
  color: #486581;
}

.chat-history {
  min-height: 300px;
  max-height: 420px;
  overflow-y: auto;
  border: 1px solid #d9e2ec;
  border-radius: 10px;
  padding: 14px;
  margin-bottom: 16px;
  background: #f8fbff;
}

.message {
  margin: 0 0 12px;
  padding: 10px 12px;
  border-radius: 8px;
  line-height: 1.4;
  white-space: pre-wrap;
}

.message.user {
  background: #d9efff;
}

.message.assistant {
  background: #ebfbee;
}

.chat-form {
  display: flex;
  gap: 8px;
}

#prompt {
  flex: 1;
  padding: 10px;
  border: 1px solid #bcccdc;
  border-radius: 8px;
}

#sendButton {
  padding: 10px 16px;
  border: none;
  border-radius: 8px;
  background: #0b7285;
  color: #fff;
  cursor: pointer;
}

#sendButton:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}