:root {
  color-scheme: light dark;
  --bg: #f5f5f7;
  --panel: #ffffff;
  --text: #1c1c1e;
  --muted: #6b6b70;
  --accent: #4f46e5;
  --accent-text: #ffffff;
  --bubble-user: #4f46e5;
  --bubble-bot: #ececee;
  --border: #e2e2e6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121214;
    --panel: #1c1c1f;
    --text: #f0f0f2;
    --muted: #9a9aa0;
    --accent: #6366f1;
    --accent-text: #ffffff;
    --bubble-user: #6366f1;
    --bubble-bot: #2a2a2e;
    --border: #2e2e33;
  }
}

* {
  box-sizing: border-box;
}

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

.view {
  width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

.hidden {
  display: none !important;
}

/* Landing page */
#landing {
  align-items: center;
  justify-content: center;
  padding: 2rem;
  gap: 2rem;
  overflow-y: auto;
}

#landing h1 {
  font-size: 1.75rem;
  margin: 0;
  text-align: center;
}

.persona-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  max-width: 640px;
}

.persona-btn {
  padding: 1.25rem 1.75rem;
  font-size: 1.05rem;
  font-weight: 600;
  border: none;
  border-radius: 14px;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
  cursor: pointer;
  min-width: 140px;
  transition: transform 0.12s ease, background 0.12s ease;
}

.persona-btn:hover {
  transform: translateY(-2px);
  background: var(--accent);
  color: var(--accent-text);
}

/* Chat page */
#chat {
  width: 100%;
  max-width: 720px;
  padding: 0 1rem;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

.chat-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 0.25rem;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.back-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.75rem;
  cursor: pointer;
  color: var(--text);
  font-size: 0.9rem;
}

.chat-header h2 {
  margin: 0;
  font-size: 1.2rem;
}

#chat-log {
  flex: 1;
  overflow-y: auto;
  padding: 1rem 0.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  min-height: 0;
}

.msg {
  max-width: 75%;
  padding: 0.6rem 0.9rem;
  border-radius: 16px;
  line-height: 1.4;
  white-space: pre-wrap;
  word-wrap: break-word;
}

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

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

.msg.error {
  align-self: flex-start;
  background: #fee2e2;
  color: #991b1b;
}

.msg.pending {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.85rem 1rem;
}

.typing-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--muted);
  animation: typing-bounce 1.2s infinite ease-in-out;
}

.typing-dot:nth-child(2) {
  animation-delay: 0.15s;
}

.typing-dot:nth-child(3) {
  animation-delay: 0.3s;
}

@keyframes typing-bounce {
  0%, 60%, 100% {
    transform: translateY(0);
    opacity: 0.5;
  }
  30% {
    transform: translateY(-4px);
    opacity: 1;
  }
}

.chat-input-row {
  display: flex;
  gap: 0.5rem;
  padding: 0.75rem 0.25rem 1.25rem;
  border-top: 1px solid var(--border);
  flex-shrink: 0;
}

#chat-input {
  flex: 1;
  padding: 0.7rem 0.9rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  font-size: 1rem;
  resize: none;
}

#send-btn {
  padding: 0 1.25rem;
  border-radius: 12px;
  border: none;
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 600;
  cursor: pointer;
}

#send-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}