:root {
  /* Colors - White, Blue, Gray Theme */
  --c-primary: #2563eb;
  --c-primary-hover: #1d4ed8;
  --c-bg: #f8fafc;
  --c-surface: #ffffff;
  --c-border: #e2e8f0;
  --c-text-main: #1e293b;
  --c-text-muted: #64748b;
  --c-success: #16a34a;
  --c-error: #dc2626;

  /* Geometry & Typography */
  --radius: 4px;
  --font-ui: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, Arial, sans-serif;
  --font-code: "JetBrains Mono", Consolas, Monaco, "Courier New", monospace;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-ui);
  font-size: 14px;
  color: var(--c-text-main);
  background-color: var(--c-bg);
  line-height: 1.5;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

a {
  color: var(--c-primary);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--c-primary-hover);
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 16px;
}

/* Common Header */
.site-header {
  background: var(--c-surface);
  border-bottom: 1px solid var(--c-border);
  position: sticky;
  top: 0;
  z-index: 100;
  display: block;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.site-header .logo {
  font-size: 16px;
  font-weight: 600;
  color: var(--c-text-main);
  display: flex;
  align-items: center;
  flex-shrink: 1;
  min-width: 0;
}

.site-header .logo span {
  color: var(--c-primary);
}

.site-nav {
  display: flex;
  gap: 20px;
  align-items: center;
  flex-shrink: 0;
}

.site-nav a {
  color: var(--c-text-muted);
  font-weight: 500;
  text-decoration: none;
}

.site-nav a.nav-login {
  color: var(--c-primary);
  border: 1px solid var(--c-primary);
  padding: 4px 12px;
  border-radius: var(--radius);
  transition: all 0.2s;
}

.site-nav a.nav-login:hover {
  background: var(--c-primary);
  color: #fff;
}

.site-nav a.nav-user {
  color: var(--c-text-main);
  display: flex;
  align-items: center;
  gap: 6px;
}

.site-nav a.nav-user .nav-user-avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: var(--c-primary);
  color: #fff;
  border-radius: 50%;
  font-size: 12px;
  font-weight: bold;
}

.site-nav a:hover, .site-nav a.active {
  color: var(--c-primary);
}

/* 主题切换按钮 */
.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  margin-right: 4px;
  border: none;
  border-radius: var(--radius);
  background: transparent;
  color: var(--c-text-muted);
  cursor: pointer;
  transition: color 0.2s;
  flex-shrink: 0;
}

.theme-toggle-btn:hover {
  color: var(--c-primary);
  background: transparent;
}

/* 语言选择器 */
.lang-switcher {
  position: relative;
  flex-shrink: 0;
}

.lang-switcher-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 12px;
  border: 1px solid var(--c-border);
  border-radius: 999px;
  background: var(--c-surface);
  color: var(--c-text-muted);
  font-size: 13px;
  font-weight: 500;
  font-family: var(--font-ui);
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s, box-shadow 0.2s;
  white-space: nowrap;
}

.lang-switcher-btn:hover,
.lang-switcher.open .lang-switcher-btn {
  color: var(--c-text-main);
  border-color: #cbd5e1;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

.lang-globe-icon,
.lang-chevron-icon {
  flex-shrink: 0;
  color: var(--c-text-muted);
}

.lang-switcher-label {
  line-height: 1;
}

.lang-chevron-icon {
  transition: transform 0.2s;
}

.lang-switcher.open .lang-chevron-icon {
  transform: rotate(180deg);
}

.lang-switcher-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 140px;
  max-height: 320px;
  overflow-y: auto;
  margin: 0;
  padding: 4px;
  list-style: none;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.12);
  z-index: 200;
}

.lang-option-label {
  font-weight: 500;
}

.lang-switcher-menu[hidden] {
  display: none;
}

.lang-switcher-option {
  display: block;
  width: 100%;
  padding: 8px 12px;
  border: none;
  border-radius: 3px;
  background: transparent;
  color: var(--c-text-main);
  font-size: 13px;
  font-family: var(--font-ui);
  text-align: left;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.lang-switcher-option:hover {
  background: var(--c-bg);
  color: var(--c-primary);
}

.lang-switcher-option.active {
  color: var(--c-primary);
  font-weight: 600;
  background: rgba(37, 99, 235, 0.06);
}

[data-theme="dark"] .lang-switcher-btn:hover,
[data-theme="dark"] .lang-switcher.open .lang-switcher-btn {
  border-color: var(--c-border);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
}

[data-theme="dark"] .lang-switcher-menu {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] .lang-switcher-option:hover {
  background: var(--c-hover-bg);
}

[data-theme="dark"] .lang-switcher-option.active {
  background: rgba(96, 165, 250, 0.12);
}

@media (max-width: 768px) {
  .site-nav {
    gap: 12px;
  }

  .lang-switcher-label {
    display: none;
  }

  .lang-switcher-btn {
    padding: 0 8px;
    gap: 4px;
  }
}

/* 暗色主题 */
[data-theme="dark"] {
  color-scheme: dark;
  --c-primary: #60a5fa;
  --c-primary-hover: #93c5fd;
  --c-bg: #0f172a;
  --c-surface: #1e293b;
  --c-border: #334155;
  --c-text-main: #f1f5f9;
  --c-text-muted: #94a3b8;
  --c-success: #4ade80;
  --c-error: #f87171;
  --c-subtle-bg: #334155;
  --c-hover-bg: #283548;
  --c-input-bg: #1e293b;
  --c-code-bg: #334155;
  --c-warning-bg: #422006;
  --c-warning-text: #fbbf24;
  --c-warning-border: #78350f;
  --c-success-bg: #052e16;
  --c-error-bg: #450a0a;
  --c-info-bg: #172554;
}

[data-theme="dark"] .site-header {
  background: rgba(15, 23, 42, 0.95);
  border-bottom-color: var(--c-border);
}

[data-theme="dark"] .btn:hover {
  border-color: var(--c-border);
  background: var(--c-hover-bg);
}

[data-theme="dark"] .btn-warning {
  background: var(--c-warning-bg);
  color: var(--c-warning-text);
  border-color: var(--c-warning-border);
}

[data-theme="dark"] .btn-warning:hover {
  background: #78350f;
  border-color: #92400e;
}

[data-theme="dark"] .filter-btn:hover {
  color: var(--c-text-main);
  border-color: var(--c-border);
  background: var(--c-hover-bg);
}

[data-theme="dark"] .filter-btn .count {
  background: var(--c-subtle-bg);
}

[data-theme="dark"] input,
[data-theme="dark"] textarea,
[data-theme="dark"] select {
  background: var(--c-input-bg);
  color: var(--c-text-main);
  border-color: var(--c-border);
}

[data-theme="dark"] input::placeholder,
[data-theme="dark"] textarea::placeholder {
  color: var(--c-text-muted);
}

[data-theme="dark"] .custom-toast {
  background: var(--c-surface);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] .custom-toast.success .custom-toast-icon {
  background-color: var(--c-success-bg);
}

[data-theme="dark"] .custom-toast.error .custom-toast-icon {
  background-color: var(--c-error-bg);
}

[data-theme="dark"] .custom-toast.info .custom-toast-icon {
  background-color: var(--c-info-bg);
}

[data-theme="dark"] .article-content strong {
  color: var(--c-text-main);
}

[data-theme="dark"] .article-content code {
  background: var(--c-code-bg);
}

[data-theme="dark"] .md-preview table.md-table th {
  background: var(--c-subtle-bg);
}

[data-theme="dark"] .md-preview table.md-table tbody tr:nth-child(even) {
  background: var(--c-hover-bg);
}

[data-theme="dark"] .md-preview pre,
[data-theme="dark"] .md-preview blockquote {
  background: var(--c-subtle-bg);
  color: var(--c-text-muted);
}

[data-theme="dark"] .tool-item,
[data-theme="dark"] .category-card,
[data-theme="dark"] .dataset-card,
[data-theme="dark"] .tool-card {
  background: var(--c-surface);
  border-color: var(--c-border);
}

[data-theme="dark"] .tool-item:hover,
[data-theme="dark"] .category-card:hover,
[data-theme="dark"] .dataset-card:hover,
[data-theme="dark"] .tool-card:hover {
  border-color: var(--c-primary);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .hero-privacy-link {
  background: rgba(74, 222, 128, 0.1);
  border-color: rgba(74, 222, 128, 0.3);
  color: var(--c-success);
}

[data-theme="dark"] .user-meta-info-bar {
  background: var(--c-surface) !important;
  border-color: var(--c-border) !important;
  color: var(--c-text-muted) !important;
}

[data-theme="dark"] .quick-workspace,
[data-theme="dark"] .home-fmt-toolbar,
[data-theme="dark"] .home-panel,
[data-theme="dark"] .home-status-bar,
[data-theme="dark"] .workspace-panel,
[data-theme="dark"] .tool-workspace,
[data-theme="dark"] .tool-panel,
[data-theme="dark"] .panel-head,
[data-theme="dark"] .tool-head-area,
[data-theme="dark"] .fmt-toolbar,
[data-theme="dark"] .status-bar {
  background: var(--c-surface);
  border-color: var(--c-border);
  color: var(--c-text-main);
}

[data-theme="dark"] .home-fmt-toolbar,
[data-theme="dark"] .home-panel-head,
[data-theme="dark"] .fmt-toolbar,
[data-theme="dark"] .panel-head {
  background: var(--c-subtle-bg);
}

[data-theme="dark"] .home-panel textarea,
[data-theme="dark"] .home-panel pre,
[data-theme="dark"] .workspace-panel textarea,
[data-theme="dark"] .workspace-panel pre,
[data-theme="dark"] .tool-panel textarea,
[data-theme="dark"] .tool-panel pre {
  background: var(--c-input-bg);
  color: var(--c-text-main);
}

[data-theme="dark"] .home-icon-btn,
[data-theme="dark"] .fmt-icon-btn,
[data-theme="dark"] .panel-action-btn {
  color: var(--c-text-muted);
  border-color: var(--c-border);
  background: var(--c-surface);
}

[data-theme="dark"] .home-icon-btn:hover,
[data-theme="dark"] .fmt-icon-btn:hover,
[data-theme="dark"] .panel-action-btn:hover {
  color: var(--c-primary);
  border-color: var(--c-primary);
  background: var(--c-hover-bg);
}

[data-theme="dark"] .home-icon-btn.active,
[data-theme="dark"] .fmt-icon-btn.active {
  color: var(--c-primary);
  background: rgba(96, 165, 250, 0.15);
  border-color: var(--c-primary);
}

[data-theme="dark"] .search-input {
  background: var(--c-input-bg);
  color: var(--c-text-main);
  border-color: var(--c-border);
}

[data-theme="dark"] .search-input:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px rgba(96, 165, 250, 0.15);
}

[data-theme="dark"] .article-container {
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] ::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

[data-theme="dark"] ::-webkit-scrollbar-track {
  background: var(--c-bg);
}

[data-theme="dark"] ::-webkit-scrollbar-thumb {
  background: var(--c-border);
  border-radius: 4px;
}

[data-theme="dark"] ::-webkit-scrollbar-thumb:hover {
  background: var(--c-text-muted);
}

[data-theme="dark"] .home-view-btn,
[data-theme="dark"] .home-indent-btn {
  background: var(--c-surface);
  color: var(--c-text-muted);
}

[data-theme="dark"] .home-view-btn:hover,
[data-theme="dark"] .home-indent-btn:hover {
  background: var(--c-hover-bg);
  color: var(--c-text-main);
}

[data-theme="dark"] .home-status-bar.success {
  background: var(--c-success-bg);
  color: var(--c-success);
}

[data-theme="dark"] .home-status-bar.error {
  background: var(--c-error-bg);
  color: var(--c-error);
}

[data-theme="dark"] .home-panel-head {
  background: var(--c-subtle-bg);
}

[data-theme="dark"] .status-bar.success,
[data-theme="dark"] .workspace-status.success {
  background: var(--c-success-bg);
  color: var(--c-success);
}

[data-theme="dark"] .status-bar.error,
[data-theme="dark"] .workspace-status.error {
  background: var(--c-error-bg);
  color: var(--c-error);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px 12px;
  font-size: 13px;
  font-family: inherit;
  font-weight: 500;
  color: var(--c-text-main);
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
  user-select: none;
}

/* 自定义高质 Toast 弹窗提示组件 Custom Toast styling */
.custom-toast-container {
  position: fixed;
  top: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 10px;
  pointer-events: none;
}

.custom-toast {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 18px;
  background: #ffffff;
  border: 1px solid var(--c-border);
  border-radius: 8px;
  box-shadow: 0 10px 15px -3px rgba(0,0,0,0.05), 0 4px 6px -4px rgba(0,0,0,0.05), 0 0 0 1px rgba(0,0,0,0.02);
  pointer-events: auto;
  opacity: 0;
  transform: scale(0.95);
  transition: all 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.1);
  min-width: 280px;
  max-width: 480px;
}

.custom-toast.show {
  opacity: 1;
  transform: scale(1) translateY(0);
}

.custom-toast-icon {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: bold;
  flex-shrink: 0;
}

.custom-toast-msg {
  font-size: 13px;
  font-weight: 500;
  color: var(--c-text-main);
  line-height: 1.4;
  flex: 1;
}

.custom-toast.success {
  border-left: 4px solid var(--c-success);
}
.custom-toast.success .custom-toast-icon {
  background-color: #f0fdf4;
  color: var(--c-success);
}

.custom-toast.error {
  border-left: 4px solid var(--c-error);
}
.custom-toast.error .custom-toast-icon {
  background-color: #fef2f2;
  color: var(--c-error);
}

.custom-toast.info {
  border-left: 4px solid var(--c-primary);
}
.custom-toast.info .custom-toast-icon {
  background-color: #eff6ff;
  color: var(--c-primary);
}

.btn:hover {
  border-color: #cbd5e1;
  background: #f1f5f9;
}

.btn-primary {
  background: var(--c-primary);
  color: #fff;
  border-color: var(--c-primary);
}

.btn-primary:hover {
  background: var(--c-primary-hover);
  border-color: var(--c-primary-hover);
  color: #fff;
}

.btn-warning {
  background: #fffbeb;
  color: #d97706;
  border-color: #fde68a;
}

.btn-warning:hover {
  background: #fef3c7;
  border-color: #fcd34d;
}

/* Filter Controls */
.filter-controls, .dataset-filters {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 32px;
}

.filter-btn {
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--c-text-muted);
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
  user-select: none;
  display: inline-flex;
  align-items: center;
}

.filter-btn:hover {
  color: var(--c-text-main);
  border-color: #cbd5e1;
  background: #f8fafc;
}

.filter-btn.active {
  color: #fff;
  background: var(--c-primary);
  border-color: var(--c-primary);
}

.filter-btn .count {
  font-size: 11px;
  background: #f1f5f9;
  color: var(--c-text-muted);
  padding: 1px 6px;
  border-radius: 10px;
  margin-left: 6px;
  font-family: var(--font-code);
  font-weight: 600;
}

.filter-btn.active .count {
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
}

/* Common Footer */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--c-border);
  background: var(--c-surface);
  padding: 20px 0;
  color: var(--c-text-muted);
  font-size: 13px;
}

.site-footer .container {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
}

.footer-right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 8px;
  flex-shrink: 0;
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer-sites {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 13px;
  line-height: 1.5;
}

.footer-sites-label {
  color: var(--c-text-muted);
  margin-right: -4px;
}

.footer-sites a {
  color: #64748b;
  text-decoration: none;
}

.footer-sites a:hover {
  color: var(--c-primary);
  text-decoration: underline;
}

[data-theme="dark"] .footer-sites a {
  color: #94a3b8;
}

[data-theme="dark"] .footer-sites a:hover {
  color: var(--c-primary);
}

.footer-beian {
  margin-top: 8px;
  font-size: 12px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
}

.footer-beian a {
  color: var(--c-text-muted);
  text-decoration: none;
}

.footer-beian a:hover {
  color: var(--c-primary);
}

.footer-company {
  color: var(--c-text-muted);
}

/* Article / Text Pages (Privacy, About) */
.article-container {
  width: 100%;
  margin: 40px 0;
  padding: 40px;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: 0 1px 3px rgba(0,0,0,0.02);
}

.article-content h1 {
  font-size: 26px;
  font-weight: 600;
  margin: 0 0 8px 0;
  color: var(--c-text-main);
}

.article-content .meta {
  color: var(--c-text-muted);
  font-size: 13px;
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--c-border);
}

.article-content h2 {
  font-size: 18px;
  font-weight: 600;
  margin: 32px 0 16px 0;
  color: var(--c-text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.article-content h2::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 16px;
  background: var(--c-primary);
  border-radius: 2px;
}

.article-content p {
  line-height: 1.8;
  margin-bottom: 16px;
  color: var(--c-text-main);
}

.article-content ul, .article-content ol {
  line-height: 1.8;
  margin-bottom: 16px;
  padding-left: 20px;
  color: var(--c-text-main);
}

.article-content li {
  margin-bottom: 8px;
}

.article-content strong {
  font-weight: 600;
  color: #0f172a;
}

.article-content code {
  font-family: var(--font-code);
  background: #f1f5f9;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
  color: var(--c-error);
}

/* Markdown 预览：数学公式与表格 */
.md-preview .math-display {
  display: block;
  margin: 16px 0;
  overflow-x: auto;
  text-align: center;
}

.md-preview .math-inline {
  display: inline;
}

.md-preview .math-error {
  color: var(--c-error);
  font-family: var(--font-code);
  font-size: 13px;
}

.md-preview table.md-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 13px;
}

.md-preview table.md-table th,
.md-preview table.md-table td {
  border: 1px solid var(--c-border);
  padding: 8px 12px;
  text-align: left;
}

.md-preview table.md-table th {
  background: #f8fafc;
  font-weight: 600;
}

.md-preview table.md-table tbody tr:nth-child(even) {
  background: #fafbfc;
}

.md-preview pre {
  background: #f8fafc;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 12px 14px;
  overflow-x: auto;
  margin: 12px 0;
}

.md-preview pre code {
  background: transparent;
  padding: 0;
  color: inherit;
}

.md-preview blockquote {
  border-left: 4px solid var(--c-primary);
  margin: 12px 0;
  padding: 8px 16px;
  color: #64748b;
  background: #f8fafc;
}

@media (max-width: 768px) {
  .article-container {
    margin: 20px 16px;
    padding: 24px;
  }
}