/* Base Reset & Variables */
:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Source Code Pro', monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);

  --sidebar-width: 280px;
  --header-height: 52px;
  --input-min-height: 56px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
}

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

html, body {
  height: 100%;
  overflow: hidden;
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover);
}

/* App Container */
.app-container {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

/* ─── Sidebar ─── */
.sidebar {
  width: var(--sidebar-width);
  min-width: 220px;
  max-width: 400px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-primary);
  display: flex;
  flex-direction: column;
  position: relative;
  z-index: 10;
  transition: width var(--transition-normal);
}

.sidebar-resize-handle {
  position: absolute;
  top: 0;
  right: -3px;
  width: 6px;
  height: 100%;
  cursor: col-resize;
  z-index: 20;
}
.sidebar-resize-handle:hover {
  background: var(--accent-primary);
  opacity: 0.3;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 18px 12px;
  color: var(--text-primary);
}
.brand-name {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* Mode Switcher */
.mode-switcher {
  display: flex;
  gap: 4px;
  padding: 0 12px;
  margin-bottom: 12px;
}
.mode-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 12px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 12px;
  font-weight: 500;
  transition: all var(--transition-fast);
}
.mode-btn:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}
.mode-btn.active {
  background: var(--accent-code-bg);
  color: var(--accent-primary);
}
.mode-btn.active[data-mode="cowork"] {
  background: var(--accent-cowork-bg);
  color: var(--accent-cowork);
}

/* Sidebar Tabs */
.sidebar-tabs {
  display: flex;
  gap: 2px;
  padding: 0 12px;
  margin-bottom: 8px;
}
.sidebar-tab {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  padding: 6px 10px;
  border: none;
  background: transparent;
  color: var(--text-tertiary);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 11px;
  font-weight: 500;
  transition: all var(--transition-fast);
}
.sidebar-tab:hover {
  color: var(--text-secondary);
  background: var(--bg-hover);
}
.sidebar-tab.active {
  color: var(--text-primary);
  background: var(--bg-active);
}

/* Sidebar Panels */
.sidebar-panel {
  display: none;
  flex: 1;
  overflow-y: auto;
  padding: 0 12px;
}
.sidebar-panel.active {
  display: flex;
  flex-direction: column;
}

.panel-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 0;
  margin-bottom: 8px;
}

/* Conversation List */
.conversation-list {
  flex: 1;
  overflow-y: auto;
}
.conversation-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-fast);
  position: relative;
}
.conversation-item:hover {
  background: var(--bg-hover);
}
.conversation-item.active {
  background: var(--bg-active);
}
.conversation-item .conv-title {
  flex: 1;
  font-size: 13px;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.conversation-item .conv-time {
  font-size: 10px;
  color: var(--text-tertiary);
}
.conversation-item .conv-delete {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  opacity: 0;
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: opacity var(--transition-fast);
}
.conversation-item:hover .conv-delete {
  opacity: 1;
}

/* Settings Form */
.settings-form {
  padding: 8px 0;
}
.settings-form h3 {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin: 16px 0 8px;
}
.settings-form h3:first-child {
  margin-top: 0;
}

/* Sidebar Footer */
.sidebar-footer {
  padding: 12px 16px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.session-stats {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--text-tertiary);
}
.session-stat-sep {
  opacity: 0.5;
}
.connection-status {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
}
.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--danger);
}
.status-dot.connected {
  background: var(--success);
}
.status-dot.connecting {
  background: var(--warning);
  animation: pulse 1.5s infinite;
}
.status-text {
  color: var(--text-tertiary);
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ─── Main Content ─── */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}
.content-area {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* Chat Container */
.chat-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

/* Chat Header */
.chat-header {
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-primary);
  flex-shrink: 0;
}
.chat-header-left {
  display: flex;
  align-items: center;
  gap: 12px;
}
.chat-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
}
.chat-model {
  font-size: 11px;
  color: var(--text-tertiary);
  background: var(--bg-tertiary);
  padding: 2px 8px;
  border-radius: var(--radius-full);
}
.chat-header-right {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* Messages Container */
.messages-container {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  position: relative;
}

/* Scroll to bottom */
.scroll-to-bottom-btn {
  position: absolute;
  bottom: 100px;
  right: 24px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-primary);
  color: var(--text-primary);
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-md);
}
.scroll-to-bottom-btn:hover {
  background: var(--accent-primary);
  color: white;
}
.scroll-to-bottom-btn.hidden {
  display: none;
}

/* Welcome Screen */
.welcome-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  padding: 40px;
}
.welcome-logo {
  color: var(--accent-primary);
  margin-bottom: 20px;
}
.welcome-screen h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}
.welcome-subtitle {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 400px;
}
.welcome-suggestions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  max-width: 500px;
}
.suggestion-chip {
  padding: 8px 16px;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-full);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.suggestion-chip:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-hover);
}

/* Input Area */
.input-area {
  padding: 12px 20px 20px;
  background: var(--bg-primary);
  border-top: 1px solid var(--border-subtle);
}
.input-wrapper {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  background: var(--bg-input);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: 8px 12px;
  transition: border-color var(--transition-fast);
}
.input-wrapper:focus-within {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.message-input {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.5;
  resize: none;
  outline: none;
  min-height: 24px;
  max-height: 200px;
}
.message-input::placeholder {
  color: var(--text-placeholder);
}
.input-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* ─── Form Elements ─── */
.form-group {
  margin-bottom: 12px;
}
.form-group label {
  display: block;
  font-size: 11px;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 4px;
}
.form-input, .form-select {
  width: 100%;
  padding: 8px 10px;
  background: var(--bg-input);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 13px;
  font-family: var(--font-sans);
  outline: none;
  transition: border-color var(--transition-fast);
}
.form-input:focus, .form-select:focus {
  border-color: var(--accent-primary);
}
.form-select {
  cursor: pointer;
}
.form-range {
  width: 100%;
  margin-top: 4px;
}
.form-actions {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}
.test-result {
  margin-top: 8px;
  font-size: 12px;
  padding: 6px 10px;
  border-radius: var(--radius-sm);
}
.test-result.success {
  background: rgba(110, 231, 160, 0.1);
  color: var(--success);
}
.test-result.error {
  background: var(--danger-bg);
  color: var(--danger);
}

/* Search Input */
.search-input {
  flex: 1;
  padding: 6px 10px;
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 12px;
  outline: none;
}
.search-input:focus {
  border-color: var(--accent-primary);
}

/* ─── Buttons ─── */
.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}
.btn-icon:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}
.btn-primary {
  padding: 8px 16px;
  background: var(--accent-primary);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}
.btn-primary:hover {
  background: var(--accent-hover);
}
.btn-secondary {
  padding: 8px 16px;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.btn-secondary:hover {
  background: var(--bg-hover);
  border-color: var(--border-hover);
}
.btn-danger {
  padding: 8px 16px;
  background: var(--danger);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}
.send-btn {
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: var(--radius-md);
}
.stop-btn {
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: var(--radius-md);
}

/* Hidden utility */
.hidden {
  display: none !important;
}

/* ─── Responsive ─── */
@media (max-width: 768px) {
  .sidebar {
    position: absolute;
    left: -100%;
    top: 0;
    bottom: 0;
    z-index: 100;
    transition: left var(--transition-normal);
  }
  .sidebar.open {
    left: 0;
  }
  .app-container {
    position: relative;
  }
}