:root {
  --bg: #f7f7f5;
  --fg: #1a1a1a;
  --muted: #6b6b6b;
  --accent: #2f6f4f;
  --accent-fg: #ffffff;
  --bubble-user: #2f6f4f;
  --bubble-user-fg: #ffffff;
  --bubble-bot: #ffffff;
  --bubble-bot-fg: #1a1a1a;
  --border: #e2e0da;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16171a;
    --fg: #ececec;
    --muted: #9a9a9a;
    --accent: #4fae7c;
    --accent-fg: #0b0f0d;
    --bubble-user: #4fae7c;
    --bubble-user-fg: #0b0f0d;
    --bubble-bot: #23252a;
    --bubble-bot-fg: #ececec;
    --border: #2c2e33;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  padding: 24px 16px 12px;
  text-align: center;
}

header h1 {
  margin: 0 0 4px;
  font-size: 1.6rem;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

main {
  flex: 1;
  width: 100%;
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px 24px;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.chat {
  flex: 1;
  min-height: 240px;
  overflow-y: auto;
  padding: 12px 4px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.bubble {
  max-width: 85%;
  padding: 10px 14px;
  border-radius: 14px;
  line-height: 1.45;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.bubble.user {
  align-self: flex-end;
  background: var(--bubble-user);
  color: var(--bubble-user-fg);
  border-bottom-right-radius: 4px;
}

.bubble.bot {
  align-self: flex-start;
  background: var(--bubble-bot);
  color: var(--bubble-bot-fg);
  border: 1px solid var(--border);
  border-bottom-left-radius: 4px;
}

.bubble.error {
  align-self: flex-start;
  background: transparent;
  color: #c0392b;
  border: 1px solid #c0392b;
}

.sources {
  margin-top: 8px;
  font-size: 0.8rem;
  color: var(--muted);
}

.sources a {
  color: inherit;
}

.chat-form {
  display: flex;
  gap: 8px;
  border-top: 1px solid var(--border);
  padding-top: 12px;
}

textarea {
  flex: 1;
  resize: none;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bubble-bot);
  color: var(--fg);
  font-size: 1rem;
  font-family: inherit;
}

button {
  padding: 0 20px;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: var(--accent-fg);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}

button:disabled {
  opacity: 0.6;
  cursor: default;
}

.disclaimer {
  margin: 12px 0 0;
  font-size: 0.78rem;
  color: var(--muted);
  text-align: center;
}