*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --green-50: #f0fdf4;
  --green-100: #dcfce7;
  --green-200: #bbf7d0;
  --green-400: #4ade80;
  --green-500: #22c55e;
  --green-600: #16a34a;
  --green-700: #15803d;
  --green-800: #166534;
  --green-900: #14532d;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --radius: 12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--gray-50);
  color: var(--gray-800);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: stretch;
  padding: 0;
  margin: 0;
}

.app {
  width: 100%;
  background: var(--gray-50);
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* Header */
header {
  padding: 24px 24px 16px;
  background: linear-gradient(135deg, var(--green-700), var(--green-600));
  color: white;
  text-align: center;
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.menu-btn, .new-chat-btn {
  background: none;
  border: none;
  color: white;
  font-size: 1.3rem;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 8px;
  opacity: 0.85;
  transition: opacity 0.2s;
}

.menu-btn:hover, .new-chat-btn:hover {
  opacity: 1;
  background: rgba(255,255,255,0.15);
}

.leaf {
  font-size: 2rem;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.tagline {
  margin-top: 6px;
  font-size: 0.85rem;
  opacity: 0.9;
}

/* Status bar */
.status-bar {
  padding: 12px 24px;
  background: var(--green-50);
  border-bottom: 1px solid var(--green-200);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.status-text {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--green-800);
}

.spinner {
  width: 14px;
  height: 14px;
  border: 2px solid var(--green-200);
  border-top-color: var(--green-600);
  border-radius: 50%;
  display: inline-block;
}

.spinner.ready {
  border: 2px solid var(--green-500);
  background: var(--green-500);
  animation: none;
}

.spinner.loading {
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.progress-wrap {
  width: 100%;
  height: 6px;
  background: var(--green-100);
  border-radius: 3px;
  overflow: hidden;
}

.progress-wrap.hidden {
  display: none;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--green-400), var(--green-600));
  border-radius: 3px;
  transition: width 0.3s ease;
}

/* Chat area */
.chat-container {
  flex: 1;
  overflow-y: auto;
  padding: 16px 24px;
}

.messages {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.message {
  display: flex;
  max-width: 85%;
}

.message.user {
  align-self: flex-end;
}

.message.assistant {
  align-self: flex-start;
}

.bubble {
  padding: 12px 16px;
  border-radius: var(--radius);
  font-size: 0.92rem;
  line-height: 1.55;
  word-wrap: break-word;
}

.message.user .bubble {
  background: var(--green-600);
  color: white;
  border-bottom-right-radius: 4px;
}

.message.assistant .bubble {
  background: var(--green-100);
  color: var(--gray-800);
  border-bottom-left-radius: 4px;
}

.message.assistant .bubble strong {
  color: var(--green-700);
}

/* Typing indicator */
.typing-indicator {
  display: flex;
  gap: 4px;
  padding: 12px 16px;
}

.typing-indicator span {
  width: 8px;
  height: 8px;
  background: var(--green-400);
  border-radius: 50%;
  animation: bounce 1.2s ease-in-out infinite;
}

.typing-indicator span:nth-child(2) { animation-delay: 0.2s; }
.typing-indicator span:nth-child(3) { animation-delay: 0.4s; }

@keyframes bounce {
  0%, 60%, 100% { transform: translateY(0); }
  30% { transform: translateY(-6px); }
}

/* Input area */
.input-area {
  padding: 16px 24px;
  border-top: 1px solid var(--gray-200);
  background: white;
}

.btn {
  border: none;
  cursor: pointer;
  font-weight: 600;
  border-radius: var(--radius);
  font-size: 0.9rem;
  transition: all 0.2s ease;
}

.btn-load {
  width: 100%;
  padding: 14px;
  background: linear-gradient(135deg, var(--green-600), var(--green-500));
  color: white;
  font-size: 1rem;
}

.btn-load:hover {
  background: linear-gradient(135deg, var(--green-700), var(--green-600));
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(22, 163, 74, 0.3);
}

.btn-load:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.chat-input-wrap {
  display: flex;
  gap: 10px;
  align-items: flex-end;
}

.chat-input-wrap.hidden {
  display: none;
}

.mobile-warning {
  background: #fef3c7;
  color: #92400e;
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 0.82rem;
  line-height: 1.5;
  text-align: center;
  margin-bottom: 8px;
}
.mobile-warning a { color: #15803d; font-weight: 600; }
.mobile-warning.hidden { display: none; }

#user-input {
  flex: 1;
  padding: 12px 16px;
  border: 2px solid var(--green-200);
  border-radius: var(--radius);
  font-size: 0.92rem;
  font-family: inherit;
  resize: none;
  outline: none;
  transition: border-color 0.2s;
  max-height: 120px;
}

#user-input:focus {
  border-color: var(--green-500);
}

.btn-send {
  width: 46px;
  height: 46px;
  background: var(--green-600);
  color: white;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.btn-send:hover {
  background: var(--green-700);
}

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

.btn-clear {
  width: 46px;
  height: 46px;
  background: var(--gray-100);
  color: var(--gray-600);
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.btn-clear:hover {
  background: #fee2e2;
  color: #dc2626;
}

/* Footer */
footer {
  padding: 12px 24px;
  background: var(--green-50);
  border-top: 1px solid var(--green-100);
  text-align: center;
}

.eco-stats {
  display: flex;
  justify-content: center;
  gap: 20px;
  font-size: 0.78rem;
  color: var(--green-700);
  margin-bottom: 4px;
}

.footer-note {
  font-size: 0.72rem;
  color: var(--gray-600);
}

/* Scrollbar */
.chat-container::-webkit-scrollbar {
  width: 6px;
}

.chat-container::-webkit-scrollbar-track {
  background: transparent;
}

.chat-container::-webkit-scrollbar-thumb {
  background: var(--green-300);
  border-radius: 3px;
}

/* Responsive */
@media (max-width: 600px) {
  body { padding: 0; }
  .app {
    height: 100vh;
    border-radius: 0;
  }
  header h1 { font-size: 1.2rem; }
  .eco-stats { flex-direction: column; gap: 4px; }
}

/* Sidebar */
.sidebar-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 100;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
}
.sidebar-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 280px;
  height: 100vh;
  background: white;
  z-index: 200;
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
  box-shadow: 4px 0 20px rgba(0,0,0,0.15);
}
.sidebar.open {
  transform: translateX(0);
}

.sidebar-header {
  padding: 20px;
  background: var(--green-700);
  color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 700;
  font-size: 1.1rem;
}

.sidebar-close {
  background: none;
  border: none;
  color: white;
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0 4px;
  opacity: 0.8;
}
.sidebar-close:hover { opacity: 1; }

.sidebar-new-chat {
  margin: 12px 16px 4px;
  padding: 10px;
  background: var(--green-50);
  border: 1px solid var(--green-200);
  border-radius: 10px;
  color: var(--green-700);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.2s;
}
.sidebar-new-chat:hover {
  background: var(--green-100);
}

.chat-list {
  flex: 1;
  overflow-y: auto;
  padding: 8px 12px;
}

.no-chats {
  text-align: center;
  color: var(--gray-300);
  padding: 32px 16px;
  font-size: 0.9rem;
}

.chat-item {
  display: flex;
  align-items: center;
  padding: 10px 12px;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.15s;
  gap: 8px;
}
.chat-item:hover { background: var(--gray-100); }
.chat-item.active { background: var(--green-50); }

.chat-item-text {
  flex: 1;
  min-width: 0;
}

.chat-item-title {
  font-size: 0.85rem;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--gray-800);
}

.chat-item-meta {
  font-size: 0.72rem;
  color: var(--gray-300);
  margin-top: 2px;
}

.chat-item-del {
  background: none;
  border: none;
  color: var(--gray-300);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 2px 6px;
  border-radius: 6px;
  flex-shrink: 0;
}
.chat-item-del:hover {
  color: #dc2626;
  background: #fee2e2;
}