/* ==================== CSS Variables / Design Tokens ==================== */
:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-xs: 4px; --space-sm: 8px; --space-md: 16px; --space-lg: 24px; --space-xl: 32px; --space-2xl: 48px;

  /* Radius */
  --radius-sm: 8px; --radius-md: 12px; --radius-lg: 16px; --radius-xl: 20px; --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Sidebar */
  --sidebar-width: 280px;
}

/* Dark Theme (default) */
[data-theme="dark"] {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a2e;
  --bg-surface: #16162a;
  --bg-surface-hover: #1e1e3a;
  --bg-input: #1a1a2e;
  --border-color: rgba(255,255,255,0.08);
  --border-hover: rgba(255,255,255,0.15);
  --text-primary: #f0f0f5;
  --text-secondary: #9898b0;
  --text-muted: #5a5a78;
  --accent: #7c5cfc;
  --accent-hover: #6a48e8;
  --accent-glow: rgba(124,92,252,0.25);
  --accent-soft: rgba(124,92,252,0.12);
  --success: #34d399;
  --warning: #fbbf24;
  --danger: #f87171;
  --info: #60a5fa;
  --user-bubble: linear-gradient(135deg, #7c5cfc 0%, #5b3cc4 100%);
  --bot-bubble: #1a1a2e;
  --kpi-gradient-1: linear-gradient(135deg, #7c5cfc22, #7c5cfc08);
  --kpi-gradient-2: linear-gradient(135deg, #34d39922, #34d39908);
  --kpi-gradient-3: linear-gradient(135deg, #fbbf2422, #fbbf2408);
  --kpi-gradient-4: linear-gradient(135deg, #60a5fa22, #60a5fa08);
  --scrollbar-thumb: rgba(255,255,255,0.1);
  --scrollbar-track: transparent;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.5);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.6);
  --glass: rgba(22,22,42,0.8);
  --glass-border: rgba(255,255,255,0.06);
}

/* Light Theme */
[data-theme="light"] {
  --bg-primary: #f8f9fc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f0f1f5;
  --bg-surface: #ffffff;
  --bg-surface-hover: #f5f5fa;
  --bg-input: #f0f1f5;
  --border-color: rgba(0,0,0,0.08);
  --border-hover: rgba(0,0,0,0.15);
  --text-primary: #1a1a2e;
  --text-secondary: #64648a;
  --text-muted: #9898b0;
  --accent: #7c5cfc;
  --accent-hover: #6a48e8;
  --accent-glow: rgba(124,92,252,0.2);
  --accent-soft: rgba(124,92,252,0.08);
  --success: #059669;
  --warning: #d97706;
  --danger: #dc2626;
  --info: #2563eb;
  --user-bubble: linear-gradient(135deg, #7c5cfc 0%, #5b3cc4 100%);
  --bot-bubble: #ffffff;
  --kpi-gradient-1: linear-gradient(135deg, #7c5cfc18, #7c5cfc05);
  --kpi-gradient-2: linear-gradient(135deg, #059669 18, #05966905);
  --kpi-gradient-3: linear-gradient(135deg, #d9770618, #d9770605);
  --kpi-gradient-4: linear-gradient(135deg, #2563eb18, #2563eb05);
  --scrollbar-thumb: rgba(0,0,0,0.15);
  --scrollbar-track: transparent;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
  --glass: rgba(255,255,255,0.85);
  --glass-border: rgba(0,0,0,0.06);
}

/* ==================== Reset & Base ==================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  display: flex;
  height: 100vh;
  overflow: hidden;
  transition: background var(--transition-base), color var(--transition-base);
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--scrollbar-track); }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: var(--radius-full); }

/* ==================== Sidebar ==================== */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  height: 100vh;
  transition: transform var(--transition-base), min-width var(--transition-base), width var(--transition-base);
  z-index: 100;
}

.sidebar.collapsed { min-width: 0; width: 0; overflow: hidden; border-right: none; }

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--border-color);
  min-height: 64px;
}

.logo { display: flex; align-items: center; gap: var(--space-sm); }
.logo-icon { font-size: 1.5rem; }
.logo-text { font-weight: 700; font-size: 1.1rem; background: linear-gradient(135deg, var(--accent), #a78bfa); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }

.sidebar-toggle {
  background: none; border: none; color: var(--text-secondary); cursor: pointer; padding: var(--space-xs);
  border-radius: var(--radius-sm); transition: all var(--transition-fast);
}
.sidebar-toggle:hover { color: var(--text-primary); background: var(--bg-tertiary); }

.new-chat-btn {
  display: flex; align-items: center; gap: var(--space-sm); margin: var(--space-md) var(--space-lg);
  padding: var(--space-sm) var(--space-md); background: var(--accent); color: white; border: none;
  border-radius: var(--radius-md); cursor: pointer; font-weight: 600; font-size: 0.875rem;
  transition: all var(--transition-fast); justify-content: center;
}
.new-chat-btn:hover { background: var(--accent-hover); box-shadow: 0 0 20px var(--accent-glow); transform: translateY(-1px); }

.sidebar-section { padding: var(--space-sm) var(--space-md); flex: 1; overflow-y: auto; }
.sidebar-section-title { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--text-muted); padding: var(--space-sm) var(--space-sm); font-weight: 600; }

.source-item, .session-item {
  display: flex; align-items: center; gap: var(--space-sm); padding: var(--space-sm) var(--space-sm);
  border-radius: var(--radius-sm); cursor: pointer; font-size: 0.85rem; color: var(--text-secondary);
  transition: all var(--transition-fast); white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.source-item:hover, .session-item:hover { background: var(--bg-surface-hover); color: var(--text-primary); }
.session-item.active { background: var(--accent-soft); color: var(--accent); }

.source-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--success); flex-shrink: 0; }

.sidebar-footer {
  padding: var(--space-md) var(--space-lg); border-top: 1px solid var(--border-color);
  display: flex; align-items: center; justify-content: space-between;
}

.theme-toggle {
  background: var(--bg-tertiary); border: 1px solid var(--border-color); color: var(--text-secondary);
  cursor: pointer; padding: var(--space-sm); border-radius: var(--radius-sm);
  transition: all var(--transition-fast); display: flex; align-items: center;
}
.theme-toggle:hover { color: var(--text-primary); border-color: var(--border-hover); }

[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

.cms-link {
  display: flex; align-items: center; gap: var(--space-xs); font-size: 0.8rem;
  color: var(--text-secondary); text-decoration: none; padding: var(--space-sm) var(--space-sm);
  border-radius: var(--radius-sm); transition: all var(--transition-fast);
}
.cms-link:hover { color: var(--accent); background: var(--accent-soft); }

/* ==================== Main Content ==================== */
.main-content {
  flex: 1; display: flex; flex-direction: column; height: 100vh;
  background: var(--bg-primary); position: relative; overflow: hidden;
}

/* ==================== Welcome Screen ==================== */
.welcome-screen {
  flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center;
  padding: var(--space-2xl); gap: var(--space-xl); animation: fadeIn 0.6s ease;
}

@keyframes fadeIn { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: translateY(0); } }

.welcome-hero { text-align: center; }
.welcome-avatar { font-size: 4rem; margin-bottom: var(--space-md); animation: float 3s ease-in-out infinite; }
@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

.welcome-title {
  font-size: 2.5rem; font-weight: 700;
  background: linear-gradient(135deg, var(--accent), #a78bfa, #c084fc);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  margin-bottom: var(--space-sm);
}
.welcome-subtitle { color: var(--text-secondary); font-size: 1.05rem; max-width: 500px; line-height: 1.6; }

.suggestion-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: var(--space-md); max-width: 600px; width: 100%; }

.suggestion-card {
  background: var(--bg-surface); border: 1px solid var(--border-color);
  border-radius: var(--radius-md); padding: var(--space-md); cursor: pointer;
  transition: all var(--transition-base); font-size: 0.9rem; color: var(--text-secondary); line-height: 1.5;
}
.suggestion-card:hover {
  border-color: var(--accent); background: var(--accent-soft);
  color: var(--text-primary); transform: translateY(-2px); box-shadow: 0 4px 20px var(--accent-glow);
}

/* ==================== Chat Area ==================== */
.chat-area { flex: 1; overflow-y: auto; padding: var(--space-lg) var(--space-xl); padding-bottom: 0; }

.chat-messages {
  max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: var(--space-lg);
  padding-bottom: var(--space-lg);
}

/* Message bubbles */
.message { display: flex; gap: var(--space-md); animation: msgIn 0.35s ease; }
@keyframes msgIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }

.message.user { flex-direction: row-reverse; }

.message-avatar {
  width: 36px; height: 36px; border-radius: var(--radius-sm); display: flex;
  align-items: center; justify-content: center; font-size: 1.1rem; flex-shrink: 0;
  background: var(--bg-tertiary);
}
.message.user .message-avatar { background: var(--user-bubble); }

.message-body { max-width: 90%; min-width: 0; }

.message-content {
  padding: var(--space-md) var(--space-lg); border-radius: var(--radius-lg); line-height: 1.65;
  font-size: 0.92rem;
}
.message.user .message-content {
  background: var(--user-bubble); color: white;
  border-bottom-right-radius: var(--space-xs);
}
.message.bot .message-content {
  background: var(--bot-bubble); border: 1px solid var(--border-color);
  border-bottom-left-radius: var(--space-xs);
}

.message-content p { margin-bottom: 0.5em; }
.message-content p:last-child { margin-bottom: 0; }
.message-content code { font-family: var(--font-mono); background: rgba(124,92,252,0.15); padding: 2px 6px; border-radius: 4px; font-size: 0.85em; }
.message-content pre { background: var(--bg-tertiary); padding: var(--space-md); border-radius: var(--radius-sm); overflow-x: auto; margin: var(--space-sm) 0; }
.message-content pre code { background: none; padding: 0; }

/* ==================== KPI Cards ==================== */
.kpi-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: var(--space-md); margin: var(--space-md) 0; }

.kpi-card {
  background: var(--bg-surface); border: 1px solid var(--border-color);
  border-radius: var(--radius-md); padding: var(--space-md); text-align: center;
  transition: all var(--transition-fast);
}
.kpi-card:nth-child(1) { background: var(--kpi-gradient-1); border-color: rgba(124,92,252,0.2); }
.kpi-card:nth-child(2) { background: var(--kpi-gradient-2); border-color: rgba(52,211,153,0.2); }
.kpi-card:nth-child(3) { background: var(--kpi-gradient-3); border-color: rgba(251,191,36,0.2); }
.kpi-card:nth-child(4) { background: var(--kpi-gradient-4); border-color: rgba(96,165,250,0.2); }

.kpi-label { font-size: 0.75rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: var(--space-xs); }
.kpi-value { font-size: 1.5rem; font-weight: 700; color: var(--text-primary); }
.kpi-delta { font-size: 0.8rem; margin-top: var(--space-xs); font-weight: 600; }
.kpi-delta.up { color: var(--success); }
.kpi-delta.down { color: var(--danger); }
.kpi-delta.neutral { color: var(--text-muted); }

/* ==================== Chart Container ==================== */
.chart-container {
  background: var(--bg-surface); border: 1px solid var(--border-color);
  border-radius: var(--radius-md); padding: var(--space-lg); margin: var(--space-md) 0;
  position: relative; max-height: 350px;
}
.chart-container canvas { max-height: 300px; }

/* ==================== Data Table ==================== */
.data-table-wrapper {
  overflow-x: auto; margin: var(--space-md) 0; border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}
.data-table {
  width: 100%; border-collapse: collapse; font-size: 0.85rem;
}
.data-table th {
  background: var(--bg-tertiary); padding: var(--space-sm) var(--space-md); text-align: left;
  font-weight: 600; color: var(--text-secondary); white-space: nowrap;
  border-bottom: 1px solid var(--border-color); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.04em;
}
.data-table td {
  padding: var(--space-sm) var(--space-md); border-bottom: 1px solid var(--border-color);
  color: var(--text-primary);
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tr:hover td { background: var(--bg-surface-hover); }

/* ==================== Insights ==================== */
.insights-list { display: flex; flex-direction: column; gap: var(--space-sm); margin: var(--space-md) 0; }

.insight-item {
  display: flex; align-items: flex-start; gap: var(--space-sm); padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm); font-size: 0.88rem; line-height: 1.5;
}
.insight-item.positive { background: rgba(52,211,153,0.1); color: var(--success); }
.insight-item.warning { background: rgba(251,191,36,0.1); color: var(--warning); }
.insight-item.info { background: rgba(96,165,250,0.1); color: var(--info); }

.insight-icon { font-size: 1rem; flex-shrink: 0; margin-top: 2px; }

/* SQL Display */
.sql-display {
  background: var(--bg-tertiary); border: 1px solid var(--border-color);
  border-radius: var(--radius-sm); padding: var(--space-md); margin: var(--space-sm) 0;
  font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-secondary);
  overflow-x: auto; position: relative;
}
.sql-label { font-size: 0.7rem; text-transform: uppercase; color: var(--text-muted); margin-bottom: var(--space-xs); letter-spacing: 0.05em; }

/* ==================== Typing Indicator ==================== */
.typing-indicator {
  display: flex; align-items: center; gap: var(--space-sm); padding: var(--space-md) var(--space-lg);
  background: var(--bot-bubble); border: 1px solid var(--border-color);
  border-radius: var(--radius-lg); border-bottom-left-radius: var(--space-xs); width: fit-content;
}
.typing-dots { display: flex; gap: 4px; }
.typing-dot {
  width: 8px; height: 8px; border-radius: 50%; background: var(--accent);
  animation: typingBounce 1.4s ease-in-out infinite;
}
.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }
@keyframes typingBounce { 0%,60%,100% { transform: translateY(0); opacity: 0.4; } 30% { transform: translateY(-6px); opacity: 1; } }

/* ==================== Input Area ==================== */
.input-area {
  padding: var(--space-md) var(--space-xl) var(--space-lg);
  background: linear-gradient(to top, var(--bg-primary) 80%, transparent);
}

.input-container {
  max-width: 800px; margin: 0 auto; display: flex; align-items: flex-end; gap: var(--space-sm);
  background: var(--bg-input); border: 1px solid var(--border-color);
  border-radius: var(--radius-lg); padding: var(--space-sm) var(--space-sm) var(--space-sm) var(--space-md);
  transition: all var(--transition-fast);
}
.input-container:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow); }

.chat-input {
  flex: 1; background: none; border: none; outline: none; color: var(--text-primary);
  font-family: var(--font-sans); font-size: 0.95rem; resize: none; line-height: 1.5;
  max-height: 120px; padding: var(--space-sm) 0;
}
.chat-input::placeholder { color: var(--text-muted); }

.send-btn {
  width: 40px; height: 40px; border-radius: var(--radius-md);
  background: var(--accent); color: white; border: none; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all var(--transition-fast); flex-shrink: 0;
}
.send-btn:hover:not(:disabled) { background: var(--accent-hover); transform: scale(1.05); }
.send-btn:disabled { opacity: 0.4; cursor: not-allowed; }

.input-hint {
  text-align: center; font-size: 0.72rem; color: var(--text-muted); margin-top: var(--space-xs);
}
.input-hint kbd {
  background: var(--bg-tertiary); padding: 1px 5px; border-radius: 4px;
  border: 1px solid var(--border-color); font-family: var(--font-sans); font-size: 0.7rem;
}

/* ==================== Mobile ==================== */
.mobile-menu-btn {
  display: none; position: fixed; top: var(--space-md); left: var(--space-md);
  z-index: 200; background: var(--bg-surface); border: 1px solid var(--border-color);
  color: var(--text-primary); border-radius: var(--radius-sm); padding: var(--space-sm);
  cursor: pointer;
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed; left: 0; top: 0; height: 100vh;
    transform: translateX(-100%); z-index: 300;
  }
  .sidebar.open { transform: translateX(0); box-shadow: var(--shadow-lg); }
  .mobile-menu-btn { display: flex; }
  .welcome-title { font-size: 1.8rem; }
  .suggestion-grid { grid-template-columns: 1fr; }
  .input-area { padding: var(--space-sm) var(--space-md) var(--space-md); }
  .chat-area { padding: var(--space-md); }
  .kpi-grid { grid-template-columns: repeat(2, 1fr); }
  
  .message-content { padding: var(--space-sm) var(--space-md); }
  .message { gap: var(--space-sm); }
}

@media (max-width: 480px) {
  .welcome-title { font-size: 1.5rem; }
  .welcome-avatar { font-size: 3rem; }
  .welcome-subtitle { font-size: 0.9rem; }
  .kpi-grid { grid-template-columns: 1fr; }
  .input-container { flex-direction: column; align-items: stretch; border-radius: var(--radius-md); }
  .send-btn { width: 100%; border-radius: var(--radius-sm); margin-top: var(--space-xs); }
}

/* ==================== Toast ==================== */
.toast-container { position: fixed; bottom: var(--space-lg); right: var(--space-lg); z-index: 1000; display: flex; flex-direction: column; gap: var(--space-sm); }

.toast {
  padding: var(--space-md) var(--space-lg); border-radius: var(--radius-md);
  font-size: 0.88rem; color: white; animation: toastIn 0.3s ease, toastOut 0.3s ease 3.7s forwards;
  box-shadow: var(--shadow-lg); max-width: 360px;
}
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }
.toast.info { background: var(--info); }

@keyframes toastIn { from { opacity: 0; transform: translateX(40px); } to { opacity: 1; transform: translateX(0); } }
@keyframes toastOut { from { opacity: 1; } to { opacity: 0; transform: translateY(10px); } }

/* ==================== Loading skeleton ==================== */
.skeleton { background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--bg-surface-hover) 50%, var(--bg-tertiary) 75%); background-size: 200% 100%; animation: shimmer 1.5s infinite; border-radius: var(--radius-sm); }
@keyframes shimmer { 0% { background-position: 200% 0; } 100% { background-position: -200% 0; } }

/* ==================== Error state ==================== */
.error-message {
  background: rgba(248,113,113,0.1); border: 1px solid rgba(248,113,113,0.3);
  border-radius: var(--radius-md); padding: var(--space-md); color: var(--danger);
  font-size: 0.9rem; display: flex; align-items: flex-start; gap: var(--space-sm);
}