/* ========================================
   AI 智能对话 - 主样式表
   ======================================== */

/* ========================================
   1. CSS Custom Properties — Light & Dark themes
   ======================================== */
:root {
  /* Light theme */
  --bg-primary: #ffffff;
  --bg-secondary: #f7f7f8;
  --bg-tertiary: #e8e8e8;
  --bg-hover: #f0f0f0;
  --text-primary: #1a1a1d;
  --text-secondary: #6b6b6b;
  --text-tertiary: #9ca3af;
  --border-color: #e5e7eb;
  --accent-color: #6366f1;
  --accent-hover: #4f46e5;
  --accent-light: #eef2ff;
  --user-msg-bg: #6366f1;
  --user-msg-text: #ffffff;
  --ai-msg-bg: #f9fafb;
  --ai-msg-text: #1a1a1d;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --sidebar-width: 280px;
  --header-height: 56px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition: 0.2s ease;
  --danger-color: #ef4444;
  --success-color: #10b981;
  --overlay-bg: rgba(0, 0, 0, 0.5);
  --panel-shadow: -4px 0 16px rgba(0, 0, 0, 0.1);
}

/* Dark theme overrides */
[data-theme="dark"] {
  --bg-primary: #1a1a1d;
  --bg-secondary: #2d2d30;
  --bg-tertiary: #3a3a3d;
  --bg-hover: #3a3a3d;
  --text-primary: #e5e5e7;
  --text-secondary: #a0a0a3;
  --text-tertiary: #707073;
  --border-color: #3a3a3d;
  --accent-color: #818cf8;
  --accent-hover: #6366f1;
  --accent-light: #1e1b4b;
  --user-msg-bg: #818cf8;
  --user-msg-text: #ffffff;
  --ai-msg-bg: #2d2d30;
  --ai-msg-text: #e5e5e7;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --danger-color: #ef4444;
  --success-color: #10b981;
  --overlay-bg: rgba(0, 0, 0, 0.7);
  --panel-shadow: -4px 0 16px rgba(0, 0, 0, 0.3);
}

/* ========================================
   2. Reset & Base
   ======================================== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  overflow: hidden;
  transition: background-color var(--transition), color var(--transition);
}

/* ========================================
   3. Layout
   ======================================== */
.app-layout {
  display: flex;
  height: calc(100vh - var(--header-height));
  margin-top: var(--header-height);
}

.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  position: relative;
}

/* ========================================
   4. Header (.app-header)
   ======================================== */
.app-header {
  position: fixed;
  top: 0;
  left: 0;
  height: var(--header-height);
  width: 100%;
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}

.header-left {
  display: flex;
  align-items: center;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text-primary);
}

.logo-icon {
  color: var(--accent-color);
}

.logo-text {
  font-size: 18px;
  font-weight: 600;
}

.header-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.model-selector-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 14px;
  color: var(--text-primary);
  transition: background-color var(--transition);
}

.model-selector-btn:hover {
  background-color: var(--bg-hover);
}

.model-selector-btn:focus-visible {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 18px;
  transition: background-color var(--transition);
}

.header-btn:hover {
  background-color: var(--bg-hover);
}

.user-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background-color: var(--accent-light);
  color: var(--accent-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}

/* ========================================
   5. Sidebar (.sidebar)
   ======================================== */
.sidebar {
  width: var(--sidebar-width);
  height: 100%;
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
}

.sidebar-top {
  padding: 16px;
}

.new-chat-btn {
  width: 100%;
  padding: 10px;
  background-color: var(--accent-color);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: background-color var(--transition);
}

.new-chat-btn:hover {
  background-color: var(--accent-hover);
}

.sidebar-tools {
  padding: 8px 12px;
}

.tools-section-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  padding: 8px 12px;
  text-transform: uppercase;
}

.tools-list {
  display: flex;
  flex-direction: column;
}

.tool-item {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 10px 12px;
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 13px;
  transition: background-color var(--transition);
}

.tool-item:hover {
  background-color: var(--bg-hover);
}

.tool-item:focus-visible {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

.tool-item.disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.tool-item i {
  width: 20px;
  text-align: center;
  font-size: 16px;
}

.tool-badge {
  font-size: 10px;
  padding: 2px 6px;
  background-color: var(--bg-tertiary);
  border-radius: 10px;
  color: var(--text-tertiary);
  margin-left: auto;
}

.tool-badge.new-badge {
  color: white;
  background-color: var(--success-color);
}

.sidebar-conversations {
  flex: 1;
  overflow-y: auto;
  padding: 8px 12px;
}

.conversations-header {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  padding: 8px 12px;
}

.conversations-list {
  display: flex;
  flex-direction: column;
}

.conversation-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 13px;
  color: var(--text-secondary);
  transition: background-color var(--transition);
}

.conversation-item:hover {
  background-color: var(--bg-hover);
}

.conversation-item:focus-visible {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

.conversation-item.active {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  font-weight: 500;
}

.conversation-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.delete-conv {
  opacity: 0;
  padding: 4px;
  cursor: pointer;
  color: var(--text-tertiary);
  transition: opacity var(--transition), color var(--transition);
}

.conversation-item:hover .delete-conv {
  opacity: 1;
}

.delete-conv:hover {
  color: var(--danger-color);
}

.empty-state {
  text-align: center;
  color: var(--text-tertiary);
  font-size: 13px;
  padding: 24px;
}

.sidebar-footer {
  padding: 12px;
  border-top: 1px solid var(--border-color);
}

.sidebar-footer-btn {
  width: 100%;
  padding: 10px 12px;
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 13px;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: background-color var(--transition);
}

.sidebar-footer-btn:hover {
  background-color: var(--bg-hover);
}

.sidebar-footer-btn i:last-child {
  margin-left: auto;
}

/* ========================================
   6. Model Dropdown
   ======================================== */
.model-dropdown-overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
  opacity: 0;
  visibility: hidden;
  background-color: transparent;
  transition: opacity var(--transition), visibility var(--transition);
}

.model-dropdown-overlay.active {
  opacity: 1;
  visibility: visible;
}

.model-dropdown {
  position: absolute;
  top: calc(var(--header-height) + 8px);
  left: 50%;
  transform: translateX(-50%);
  width: 420px;
  max-height: 480px;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  z-index: 300;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition);
  overflow: hidden;
}

.model-dropdown.open {
  opacity: 1;
  visibility: visible;
}

.model-dropdown-header {
  padding: 16px 20px;
  font-size: 14px;
  font-weight: 600;
  border-bottom: 1px solid var(--border-color);
}

.model-list {
  overflow-y: auto;
  max-height: 400px;
}

.model-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  box-sizing: border-box;
  padding: 12px 20px;
  background: none;
  border: none;
  cursor: pointer;
  text-align: left;
  transition: background-color var(--transition);
}

.model-item:hover {
  background-color: var(--bg-hover);
}

.model-item.selected {
  background-color: var(--accent-light);
  border-left: 3px solid var(--accent-color);
}

.model-item-left {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 1;
}

.model-icon {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--bg-secondary);
  border-radius: var(--radius-sm);
  color: var(--accent-color);
  font-size: 16px;
}

.model-item-info {
  flex: 1;
}

.model-item-name {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.model-badge {
  font-size: 10px;
  padding: 2px 6px;
  background-color: var(--bg-tertiary);
  border-radius: 10px;
  color: var(--text-tertiary);
}

.model-badge.new-badge {
  background-color: var(--success-color);
  color: white;
}

.model-item-desc {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 2px;
}

.model-status {
  font-size: 11px;
  padding: 4px 8px;
  border-radius: 10px;
  flex-shrink: 0;
}

.model-status.free {
  background-color: var(--success-color);
  color: white;
  opacity: 0.9;
}

.model-status.pro {
  background-color: var(--accent-light);
  color: var(--accent-color);
}

/* ========================================
   7. Messages Area
   ======================================== */
.messages-container {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
}

.system-note {
  text-align: center;
  font-size: 12px;
  color: var(--text-tertiary);
  padding: 8px 16px;
  margin: 4px 0;
}

.welcome-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  padding: 40px;
}

.welcome-icon {
  font-size: 48px;
  color: var(--accent-color);
  margin-bottom: 16px;
}

.welcome-title {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 8px;
}

.welcome-subtitle {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.model-info-card {
  background-color: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: 24px;
  max-width: 400px;
  width: 100%;
}

.model-info-name {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
}

.model-info-desc {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ========================================
   8. Messages
   ======================================== */
.message {
  display: flex;
  gap: 12px;
  margin-bottom: 20px;
  animation: fadeIn 0.3s ease;
}

.message-avatar {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}

.user-message .message-avatar {
  background-color: var(--user-msg-bg);
  color: var(--user-msg-text);
}

.assistant-message .message-avatar {
  background-color: var(--accent-color);
  color: white;
}

.message-content {
  flex: 1;
  padding: 12px 16px;
  border-radius: var(--radius-lg);
  line-height: 1.6;
  font-size: 14px;
}

.user-message .message-content {
  background-color: var(--user-msg-bg);
  color: var(--user-msg-text);
}

.assistant-message .message-content {
  background-color: var(--ai-msg-bg);
  color: var(--ai-msg-text);
}

.message-content pre {
  background-color: var(--bg-tertiary);
  padding: 12px;
  border-radius: var(--radius-sm);
  overflow-x: auto;
  margin: 8px 0;
}

.message-content code {
  font-size: 13px;
  font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
}

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

.typing-indicator span {
  width: 8px;
  height: 8px;
  background-color: var(--text-tertiary);
  border-radius: 50%;
  animation: typing 1.4s infinite;
}

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

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

/* ========================================
   9. Input Area
   ======================================== */
.input-container {
  padding: 16px 24px 24px;
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border-color);
}

.input-wrapper {
  max-width: 800px;
  margin: 0 auto;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 8px 12px;
  transition: border-color var(--transition);
}

.input-wrapper:focus-within {
  border-color: var(--accent-color);
}

.input-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.input-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  font-size: 18px;
  transition: background-color var(--transition);
}

.input-btn:hover {
  background-color: var(--bg-hover);
}

.input-textarea {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.5;
  resize: none;
  font-family: inherit;
  max-height: 200px;
}

.input-footer-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 6px;
}

.input-footer-left {
  display: flex;
  align-items: center;
}

.input-model-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 12px;
  transition: background-color var(--transition);
}

.input-model-btn:hover {
  background-color: var(--bg-hover);
}

.input-footer-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.char-counter {
  font-size: 12px;
  color: var(--text-tertiary);
}

.send-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--accent-color);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 16px;
  transition: background-color var(--transition);
}

.send-btn:hover {
  background-color: var(--accent-hover);
}

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

/* ========================================
   10. Settings Panel
   ======================================== */
.overlay {
  position: fixed;
  inset: 0;
  background-color: var(--overlay-bg);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition);
  z-index: 150;
}

.overlay.active {
  opacity: 1;
  visibility: visible;
}

.settings-panel {
  position: fixed;
  right: -400px;
  top: 0;
  width: 400px;
  height: 100vh;
  background-color: var(--bg-primary);
  box-shadow: var(--panel-shadow);
  transition: right 0.3s ease;
  z-index: 200;
  overflow-y: auto;
}

.settings-panel.open {
  right: 0;
}

.settings-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.settings-header h2 {
  font-size: 18px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 8px;
}

.close-btn {
  background: none;
  border: none;
  font-size: 20px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px;
  transition: color var(--transition);
}

.close-btn:hover {
  color: var(--text-primary);
}

.settings-body {
  padding: 24px;
}

.settings-section {
  margin-bottom: 28px;
}

.settings-section h3 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.setting-item {
  margin-bottom: 16px;
}

.setting-item label {
  display: block;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.setting-input,
.setting-select {
  width: 100%;
  padding: 10px 12px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 14px;
  outline: none;
}

.setting-btn {
  margin-top: 8px;
  padding: 8px 20px;
  background-color: var(--accent-color);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 13px;
  cursor: pointer;
  transition: background-color var(--transition);
}

.setting-btn:hover {
  background-color: var(--accent-hover);
}

.setting-hint {
  font-size: 12px;
  color: var(--text-tertiary);
  margin-top: 8px;
  display: flex;
  align-items: center;
  gap: 4px;
}

.setting-hint a {
  color: var(--accent-color);
  text-decoration: none;
}

.setting-hint a:hover {
  text-decoration: underline;
}

.theme-options {
  display: flex;
  gap: 8px;
}

.theme-option {
  flex: 1;
  padding: 8px;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 13px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  transition: background-color var(--transition), border-color var(--transition), color var(--transition);
}

.theme-option.active {
  background-color: var(--accent-color);
  border-color: var(--accent-color);
  color: white;
}

.setting-range {
  width: 100%;
  accent-color: var(--accent-color);
}

/* ========================================
   11. Animations
   ======================================== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes typing {
  0%, 60%, 100% {
    transform: translateY(0);
  }
  30% {
    transform: translateY(-8px);
  }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* ========================================
   12. Scrollbar
   ======================================== */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background-color: var(--border-color);
  border-radius: 3px;
}

/* ========================================
   13. Responsive (max-width: 768px)
   ======================================== */
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: -280px;
    top: var(--header-height);
    z-index: 300;
    height: calc(100vh - var(--header-height));
    transition: left 0.3s ease;
  }

  .sidebar.mobile-open {
    left: 0;
  }

  .model-dropdown {
    width: calc(100vw - 32px);
    left: 16px;
    transform: none;
  }

  .settings-panel {
    width: 100%;
    right: -100%;
  }

  .messages-container {
    padding: 16px;
  }

  .input-container {
    padding: 12px 16px 16px;
  }
}