@charset "UTF-8";
/**
 * Platform Main Stylesheet
 * V7.2 Multi-Site Platform
 *
 * Provides base styles that all sites inherit.
 * Sites can override by adding their own stylesheets.
 */

/* ============================================
   CSS Variables
   ============================================ */
:root {
  /* Colors — bridge to site tokens (--site-primary defined in each site's tokens.css) */
  --color-primary: var(--site-primary, #2563eb);
  --color-primary-dark: var(--site-primary-dark, #1d4ed8);
  --color-secondary: #64748b;
  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;

  /* Text */
  --color-text: #1f2937;
  --color-text-light: #4b5563;
  --color-text-muted: #6b7280;

  /* Background */
  --color-bg: #ffffff;
  --color-bg-alt: #f9fafb;
  --color-bg-hover: #f3f4f6;

  /* Border */
  --color-border: #e5e7eb;
  --color-border-dark: #d1d5db;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Courier New', Consolas, Monaco, monospace;

  /* Layout */
  --container-max: 1200px;
  --header-height: 80px;

  /* Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-button: 6px;
  --radius-card: 8px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;

  /* Motion Timing */
  --dur-instant: 80ms;
  --dur-fast: 150ms;
  --dur-normal: 250ms;
  --dur-slow: 400ms;
  --ease-default: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);

  /* Shadow Scale — brand-tinted via color-mix */
  --shadow-sm: 0 1px 3px color-mix(in srgb, var(--color-primary) 6%, transparent);
  --shadow-md: 0 4px 6px color-mix(in srgb, var(--color-primary) 8%, transparent);
  --shadow-lg: 0 10px 15px color-mix(in srgb, var(--color-primary) 10%, transparent);
  --shadow-xl: 0 20px 25px color-mix(in srgb, var(--color-primary) 12%, transparent);
}

/* Print-only elements: hidden on screen, shown only when printing */
.print-only,
.worksheet-print-header {
  display: none !important;
}

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

/* A10: cross-site harmony */
html {
  font-size: 16px;
  line-height: 1.6;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* RTL Support */
[dir="rtl"] {
  text-align: right;
}

/* A10: cross-site harmony */
::selection {
  background: color-mix(in srgb, var(--color-primary) 20%, white);
  color: var(--color-text);
}

/* A10: cross-site harmony */
:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--color-primary, #2563eb) 60%, transparent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading, inherit);
  line-height: 1.25;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
}

h1 { font-size: clamp(1.75rem, 2.5vw + 1rem, 2.5rem); line-height: 1.2; letter-spacing: -0.02em; }
h2 { font-size: clamp(1.25rem, 1.5vw + 0.75rem, 1.75rem); line-height: 1.3; letter-spacing: -0.01em; }
h3 { font-size: 1.25rem; line-height: 1.4; }
h4 { font-size: 1.125rem; line-height: 1.45; }

p {
  margin-bottom: var(--spacing-md);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* ============================================
   Layout
   ============================================ */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 2rem;
}

.main-content {
  flex: 1;
  padding: var(--spacing-xl) 0;
}

/* ============================================
   Skip Link (Accessibility)
   ============================================ */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  z-index: 1000;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 0;
}

/* ============================================
   Site Header
   ============================================ */
.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
  height: var(--header-height);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: var(--spacing-lg);
}

.site-header .logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
  flex-shrink: 0;
}

.site-header .logo:hover {
  opacity: 0.85;
}

.logo-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  display: block;
}

/* Logo image: uses logo.svg which may be wide wordmark (320x96) or square icon (512x512).
   height is fixed, width adapts to aspect ratio.
   At 72px height with 320:96 ratio → renders ~240px wide. */
.logo-img {
  height: 72px;
  width: auto;
  max-width: 320px;
  flex-shrink: 0;
  display: block;
  object-fit: contain;
}

.logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.main-nav {
  flex: 1;
}

.main-nav ul {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
}

.main-nav a {
  color: var(--color-text);
  font-weight: 500;
  padding: var(--spacing-sm) 0;
}

.main-nav a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.main-nav a.active {
  color: var(--color-primary);
  font-weight: 600;
  border-bottom: 2px solid var(--color-primary);
}

.lang-switcher {
  position: relative;
  flex-shrink: 0;
  margin-left: auto;
}

.lang-switcher .lang-current {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-md);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-button);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), color var(--transition-fast);
}

.lang-switcher .lang-current:hover {
  background: var(--color-bg-hover);
  border-color: var(--color-border-dark);
}

.lang-switcher .lang-current[aria-expanded="true"] {
  background: var(--color-bg-hover);
  border-color: var(--color-primary);
}

.lang-switcher .lang-current[aria-expanded="true"] .lang-arrow {
  transform: rotate(180deg);
}

.lang-switcher .lang-code {
  min-width: 24px;
  text-align: center;
}

.lang-switcher .lang-arrow {
  transition: transform var(--transition-fast);
  color: var(--color-text-light);
}

.lang-switcher .lang-dropdown {
  position: absolute;
  top: calc(100% + 4px);
  right: 0;
  min-width: 200px;
  max-height: 400px;
  overflow-y: auto;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: opacity var(--transition-fast), visibility var(--transition-fast), transform var(--transition-fast);
  z-index: 1000;
}

.lang-switcher.open .lang-dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.lang-switcher .lang-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.875rem;
  transition: background var(--transition-fast);
  border-bottom: 1px solid var(--color-bg-alt);
  min-height: 44px;
}

.lang-switcher .lang-option:last-child {
  border-bottom: none;
}

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

.lang-switcher .lang-option.active {
  background: var(--color-primary);
  color: white;
}

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

.lang-switcher .lang-native {
  font-weight: 600;
}

.lang-switcher .lang-name {
  font-size: 0.75rem;
  color: var(--color-text-light);
}

.lang-switcher .lang-option.active .lang-name {
  color: rgba(255, 255, 255, 0.8);
}

/* ============================================
   Breadcrumb
   ============================================ */
.breadcrumb {
  margin-bottom: var(--spacing-md);
  background: transparent;
  border: none;
  padding: 0;
  text-align: left;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-start;
  list-style: none;
  padding: 0;
  margin: 0;
  gap: var(--spacing-xs);
  font-size: 0.875rem;
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
}

.breadcrumb li:not(:last-child)::after {
  content: '/';
  margin-left: var(--spacing-xs);
  color: var(--color-text-muted);
}

[dir="rtl"] .breadcrumb li:not(:last-child)::after {
  content: '\\';
  margin-left: 0;
  margin-right: var(--spacing-xs);
}

.breadcrumb a {
  color: var(--color-text-light);
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 var(--spacing-xs);
  text-decoration: none;
}

.breadcrumb [aria-current="page"] {
  color: var(--color-text);
  font-weight: 500;
}

/* ============================================
   Page Header
   ============================================ */
.page-header {
  margin-bottom: var(--spacing-xl);
}

.page-header .subtitle {
  color: var(--color-text-light);
  font-size: 1.125rem;
  margin-top: var(--spacing-sm);
}

/* ============================================
   SEO Content Blocks
   ============================================ */
.seo-components--primary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
  margin: var(--spacing-2xl) 0;
}

.seo-components--secondary {
  margin: var(--spacing-xl) 0;
}

.seo-card {
  background: var(--color-bg-alt);
  border-radius: var(--radius-card);
  padding: var(--spacing-lg);
  border-left: 4px solid var(--color-primary);
  transition: box-shadow var(--transition-fast);
}

.seo-card:hover {
  box-shadow: var(--shadow-sm);
}

.seo-card h2,
.seo-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.seo-card p {
  color: var(--color-text-light);
  line-height: 1.7;
  margin-bottom: var(--spacing-sm);
}

.seo-card p:last-child {
  margin-bottom: 0;
}

.seo-card ul,
.seo-card ol {
  color: var(--color-text-light);
  line-height: 1.7;
  padding-left: 1.5em;
  margin-bottom: var(--spacing-sm);
}

/* Secondary SEO toggle */
.content-toggle {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  overflow: hidden;
}

.content-toggle summary {
  padding: var(--spacing-md) var(--spacing-lg);
  font-weight: 600;
  cursor: pointer;
  background: var(--color-bg-alt);
  transition: background var(--transition-fast);
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.content-toggle summary::-webkit-details-marker {
  display: none;
}

.content-toggle summary::after {
  content: '+';
  font-size: 1.25rem;
  font-weight: 300;
  color: var(--color-text-muted);
  transition: transform var(--transition-fast);
}

.content-toggle[open] summary::after {
  content: '−';
}

.content-toggle summary:hover {
  background: var(--color-bg-hover);
}

.content-toggle-panel {
  padding: var(--spacing-lg);
}

.seo-more-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.seo-more-grid .seo-block {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
}

@media (max-width: 768px) {
  .seo-components--primary {
    grid-template-columns: 1fr;
  }
  .seo-more-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: 0.9375rem;
  font-weight: 500;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-button);
  background: var(--color-bg);
  color: var(--color-text);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), color var(--transition-fast);
  text-decoration: none;
  min-height: 44px;
}

.btn:hover {
  background: var(--color-bg-hover);
  border-color: var(--color-border-dark);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
}

.btn.disabled {
  opacity: 0.5;
  pointer-events: none;
}

.actions {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  flex-wrap: wrap;
}

/* Action buttons (detail page) */
.btn-print,
.btn-pdf,
.btn-answers {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: 0.9375rem;
  font-weight: 500;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-button);
  background: var(--color-bg);
  color: var(--color-text);
  cursor: pointer;
  transition: background-color var(--transition-fast),
              border-color var(--transition-fast),
              box-shadow var(--transition-fast),
              color var(--transition-fast);
  text-decoration: none;
  min-height: 44px;
}

.btn-print:hover,
.btn-pdf:hover,
.btn-answers:hover {
  background: var(--color-bg-hover);
  border-color: var(--color-border-dark);
  box-shadow: var(--shadow-sm);
  text-decoration: none;
}

.btn-print {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}

.btn-print:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: white;
}

/* ============================================
   Category List
   ============================================ */
.category-list,
.worksheet-list {
  list-style: none;
  display: grid;
  gap: var(--spacing-sm);
}

.category-list a,
.worksheet-list a {
  display: block;
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  color: var(--color-text);
  text-decoration: none;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
}

.category-list a:hover,
.worksheet-list a:hover {
  background: var(--color-bg-hover);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
  transform: translateX(4px);
}

[dir="rtl"] .category-list a:hover,
[dir="rtl"] .worksheet-list a:hover {
  transform: translateX(-4px);
}

.category-list .name {
  font-weight: 500;
  display: block;
}

.category-list .description {
  font-size: 0.875rem;
  color: var(--color-text-light);
  margin-top: var(--spacing-xs);
  display: block;
}

/* ============================================
   Empty State (no children in category)
   ============================================ */
.category-list:empty::before,
.category-grid:empty::before,
.worksheet-list:empty::before {
  content: attr(data-empty-message);
  display: block;
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-lg);
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  background: var(--color-bg-alt);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-card);
}

.category-list:empty::before { content: "No categories available yet."; }
.category-grid:empty::before { content: "No categories available yet."; }
.worksheet-list:empty::before { content: "No worksheets available yet."; }

/* ============================================
   Page Navigation
   ============================================ */
.page-navigation {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
}

.page-navigation a,
.page-navigation .btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

/* ============================================
   Site Footer
   ============================================ */
.site-footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-xl) 0;
  margin-top: auto;
}

.site-footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
  text-align: center;
}

.site-footer p {
  color: var(--color-text-light);
  font-size: 0.875rem;
  margin: 0;
}

.site-footer nav ul {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
}

.site-footer a {
  color: var(--color-text-light);
  font-size: 0.875rem;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: var(--spacing-xs) var(--spacing-sm);
  transition: color var(--transition-fast);
}

.site-footer a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

/* ============================================
   Intro & Content Sections
   ============================================ */
.intro,
.content,
.body-content {
  margin-bottom: var(--spacing-xl);
  /* Removed max-width: 800px - let container control width */
}

.intro p:last-child,
.content p:last-child,
.body-content p:last-child {
  margin-bottom: 0;
}

/* A10: cross-site harmony */
.prose, .content-section, .intro, .content-toggle-panel {
  max-width: 72ch;
}

.intro p, .content-section p, .body-content p,
.content-toggle-panel p, .seo-block p,
.prose p {
  max-width: 68ch;
}

/* ============================================
   Placeholder
   ============================================ */
.placeholder {
  background: var(--color-bg-alt);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-card);
  padding: var(--spacing-xl);
  text-align: center;
  color: var(--color-text-light);
}

.placeholder pre {
  text-align: left;
  background: var(--color-bg);
  padding: var(--spacing-md);
  border-radius: 4px;
  overflow-x: auto;
  font-size: 0.75rem;
  margin-top: var(--spacing-md);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding: var(--spacing-2xl) 0;
  text-align: center;
  max-width: 800px;
  margin: 0 auto var(--spacing-2xl);
}

.hero h1 {
  font-size: clamp(2rem, 3vw + 1rem, 3rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.hero .subtitle {
  font-size: clamp(1rem, 1.2vw + 0.5rem, 1.25rem);
  color: var(--color-text-light);
  line-height: 1.6;
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================
   Homepage Hero — Compact override
   Overrides site-level .hero padding so categories
   are visible on the first screen.
   Specificity (.homepage .hero = 0,2,0) beats .hero (0,1,0),
   site skin.css .homepage .hero rules (equal spec, loaded later) can still override.
   ============================================ */
.homepage .hero {
  padding-top: 1.5rem;
  padding-bottom: 1rem;
  margin-bottom: 0;
}
.homepage .hero h1,
.homepage .hero-title {
  font-size: clamp(1.4rem, 3.5vw, 2rem);
  margin-bottom: 0.4rem;
}
.homepage .hero .subtitle,
.homepage .hero-subtitle {
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
}
.homepage .hero-stats {
  gap: 1rem;
  margin-top: 0.6rem;
  margin-bottom: 0;
}
.homepage .stat-item {
  gap: 2px;
}
.homepage .stat-number {
  font-size: 1.2rem;
}
.homepage .stat-label {
  font-size: 0.75rem;
}
.homepage .hero-actions {
  margin-top: 0.8rem;
}

/* ============================================
   Category Grid (Homepage)
   ============================================ */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

/* ============================================
   Category Cards (Enhanced)
   ============================================ */
.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.category-card {
  display: flex;
  flex-direction: column;
  padding: var(--spacing-lg);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-sm);
  text-decoration: none;
  color: inherit;
  transition: box-shadow var(--transition-fast),
              transform var(--transition-fast),
              border-color var(--transition-fast);
}

.category-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--color-primary);
  text-decoration: none;
}

.category-card h3 {
  font-size: 1.125rem;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.category-card p {
  color: var(--color-text-light);
  font-size: 0.875rem;
  line-height: 1.5;
  margin-bottom: var(--spacing-md);
  flex: 1;
}

.category-meta {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: auto;
}

@media (max-width: 480px) {
  .categories-grid {
    grid-template-columns: 1fr;
  }
}

/* ── Icon Alignment ── */
.icon {
  vertical-align: middle;
  display: inline-block;
}

/* ── Footer Grid ── */
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-xl, 2rem);
  padding: var(--spacing-xl, 2rem) 0;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  margin-bottom: var(--spacing-sm, 0.5rem);
}

.footer-brand-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.footer-tagline {
  margin-top: var(--spacing-sm, 0.5rem);
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

.footer-links h4 {
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text);
  margin-bottom: var(--spacing-md, 1rem);
}

.footer-links ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-links li {
  margin-bottom: var(--spacing-sm, 0.5rem);
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast, 150ms ease);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-md, 1rem) 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm, 0.5rem);
}

.footer-bottom p {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin: 0;
}

.footer-attribution a {
  color: var(--color-text-muted);
  text-decoration: underline;
}

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

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg, 1.5rem);
  }
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Premium Platform Polish
   ============================================ */

/* Link hover underline animation */
.main-nav a {
  position: relative;
}
.main-nav a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--color-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.main-nav a:hover::after,
.main-nav a.active::after {
  transform: scaleX(1);
  transform-origin: left;
}

/* Page section spacing rhythm */
.page-section, .seo-components, .worksheets-section {
  margin-top: 3rem;
  margin-bottom: 3rem;
}

/* Breadcrumb polish */
.breadcrumb {
  font-size: 0.875rem;
  letter-spacing: 0.01em;
}
.breadcrumb a {
  transition: color 0.15s ease;
}
.breadcrumb a:hover {
  color: var(--color-primary);
}

/* Set switcher premium */
.set-switcher {
  display: flex;
  gap: 0.375rem;
  flex-wrap: wrap;
  align-items: center;
}
.set-btn {
  min-width: 40px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  font-weight: 500;
  font-size: 0.875rem;
  border: 1px solid var(--color-border);
  background: #fff;
  color: var(--color-text);
  transition: all 0.15s ease;
  cursor: pointer;
}
.set-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: color-mix(in srgb, var(--color-primary) 5%, white);
}
.set-btn.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  box-shadow: 0 2px 8px color-mix(in srgb, var(--color-primary) 30%, transparent);
}

/* Page navigation premium */
.page-navigation {
  gap: 1rem;
  margin: 2rem 0;
  padding: 1rem 0;
}
.page-navigation .btn-nav {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border-radius: 8px;
  font-weight: 500;
  font-size: 0.875rem;
  border: 1px solid var(--color-border);
  background: #fff;
  color: var(--color-text);
  text-decoration: none;
  transition: all 0.2s ease;
}
.page-navigation .btn-nav:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

/* ============================================
   Print Styles - Production-Ready Worksheet Output
   All sites share these rules. One fix = all sites fixed.
   ============================================ */

@media print {
  /* ===== FOUNDATION ===== */
  *,
  *::before,
  *::after {
    -webkit-print-color-adjust: exact !important;
    print-color-adjust: exact !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  /* @page rules owned by print-base.css — no duplicate here */

  html {
    font-size: 11pt !important;
  }

  body {
    background: white !important;
    color: #000 !important;
    font-size: 11pt !important;
    line-height: 1.35 !important;
    margin: 0 !important;
    padding: 0 !important;
    -webkit-font-smoothing: auto;
  }

  a {
    color: inherit !important;
    text-decoration: none !important;
  }

  /* ===== HIDE NON-PRINT ELEMENTS ===== */
  /* Comprehensive list — mirrors print-base.css Section 5 for the
     browser Ctrl+P path where .print-view class is NOT present. */
  .no-print,
  .site-header,
  .site-footer,
  .actions,
  .page-navigation,
  .page-nav,
  .breadcrumb,
  .set-switcher,
  .intro,
  .intro-section,
  .body-content,
  .body-content--collapsible,
  .page-header,
  .page-header-section,
  .seo-components,
  .seo-components--primary,
  .seo-components--secondary,
  .seo-block,
  .lang-switcher,
  .skip-link,
  .interactive-toolbar,
  .sie-wrapper,
  .detail-atom-toolbar,
  .content-type-badge,
  .puzzle-stats,
  .difficulty-badge,
  .score-panel,
  .score-retry,
  .stat-badge,
  .hero-stats,
  .category-meta,
  .subcategory-arrow,
  .canvas-palette,
  .brush-selector,
  .problem-feedback,
  .ws-result-icon,
  .variant-meta,
  .variant-chip,
  .btn-nav {
    display: none !important;
  }

  /* ===== SHOW PRINT-ONLY ELEMENTS ===== */
  .print-only {
    display: flex !important;
  }

  .worksheet-print-header {
    display: block !important;
    margin-bottom: 3mm !important; /* Tightened: was 4mm */
    padding-bottom: 2mm !important; /* Tightened: was 3mm */
    border-bottom: 2pt solid #000 !important;
  }

  .worksheet-print-header h1,
  .worksheet-print-header .print-title {
    font-size: 14pt !important;
    font-weight: 700 !important;
    color: #000 !important;
    margin: 0 0 2mm !important;
    line-height: 1.2 !important;
  }

  .worksheet-print-meta {
    display: flex !important;
    align-items: flex-end !important;
    justify-content: space-between !important;
    gap: 5mm !important;
    margin: 0 !important;
    font-size: 10pt !important;
    font-family: system-ui, sans-serif !important;
  }

  .worksheet-print-meta span {
    flex: 1 1 0 !important;
    border-bottom: 1pt solid #000 !important;
    padding-bottom: 1.5mm !important;
    min-height: 5mm !important; /* Tightened: was 7mm */
    color: #000 !important;
    font-weight: 500 !important;
  }

  /* ===== LAYOUT CONTAINERS ===== */
  .main-content {
    padding: 0 !important;
    margin: 0 !important;
  }

  .detail-page {
    padding: 0 !important;
    margin: 0 !important;
    max-width: 100% !important;
  }

  .container {
    max-width: 100% !important;
    padding: 0 !important;
  }

  /* ===== WORKSHEET CONTENT ===== */
  .worksheet-content {
    border: none !important;
    padding: 0 !important;
    margin: 0 !important;
    background: white !important;
    max-width: 100% !important;
    overflow: visible !important;
    border-radius: 0 !important;
  }

  .worksheet-content::before,
  .worksheet-content::after {
    display: none !important;
  }

  .worksheet-header {
    display: flex !important;
    justify-content: space-between !important;
    align-items: center !important;
    margin-bottom: 3mm !important;
    padding-bottom: 2mm !important;
    border-bottom: 1pt solid #000 !important;
  }

  .worksheet-title {
    font-size: 11pt !important;
    font-weight: 700 !important;
    color: #000 !important;
    margin: 0 !important;
    padding: 0 !important;
    border: none !important;
  }

  .worksheet-title::before {
    display: none !important;
  }

  .worksheet-meta {
    background: white !important;
    border: 1pt solid #000 !important;
    color: #000 !important;
    font-size: 9pt !important;
    padding: 1mm 3mm !important;
    border-radius: 2px !important;
  }

  /* ===== PROBLEMS GRID (Arithmetic / Form Exercises) ===== */
  .problems-grid {
    display: grid !important;
    grid-template-columns: 1fr 1fr !important;
    column-count: auto !important;
    column-gap: 4mm !important;
    row-gap: 2mm !important;
    align-content: start !important;
    border-top: none !important;
  }

  .problem {
    background: white !important;
    border: 1pt solid #bbb !important;
    border-left: 2pt solid #000 !important;
    border-radius: 0 !important;
    font-size: 12pt !important;
    padding: 2mm 3mm !important;
    margin-bottom: 0 !important;
    min-height: 10mm !important;
    page-break-inside: avoid !important;
    break-inside: avoid !important;
    display: flex !important;
    align-items: center !important;
    gap: 3mm !important;
  }

  .problem::before,
  .problem::after {
    display: none !important;
  }

  .problem:hover {
    transform: none !important;
  }

  /* Problem number */
  .problem .num {
    background: #f0f0f0 !important;
    color: #000 !important;
    border: 1pt solid #666 !important;
    border-radius: 2px !important;
    font-size: 8pt !important;
    font-weight: 700 !important;
    min-width: 1.4rem !important;
    height: 1.4rem !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    flex-shrink: 0 !important;
  }

  .problem .num::after {
    display: none !important;
  }

  /* Expression */
  .problem .expression {
    font-size: 12pt !important;
    color: #000 !important;
    font-weight: 600 !important;
    flex: 1 !important;
  }

  /* Answer blank line */
  .problem .blank {
    display: inline-block !important;
    border: none !important;
    border-bottom: 1.5pt solid #000 !important;
    min-width: 20mm !important;
    background: white !important;
    padding: 0 1mm !important;
    font-size: 12pt !important;
  }

  .problem .blank::before {
    display: none !important;
  }

  /* Hide answers in print (always print blank worksheet) */
  .problem .answer {
    display: none !important;
  }

  .answer-input,
  .problem .answer-input {
    display: none !important;
  }

  .show-answers .problem .answer {
    display: none !important;
  }

  .show-answers .problem .blank {
    display: inline-block !important;
  }

  .show-answers .problem {
    background: white !important;
    border-left-color: #000 !important;
  }

  .show-answers .problem::before {
    display: none !important;
  }

  /* ===== CATEGORY / LIST PAGE PRINT ===== */
  .category-card,
  .subcategory-card {
    break-inside: avoid !important;
    page-break-inside: avoid !important;
    box-shadow: none !important;
  }

  /* ===== BINGO CARDS ===== */
  .bingo-container {
    max-width: 300px !important;
    width: 300px !important;
    margin: 0 auto !important;
    page-break-inside: avoid !important;
    break-inside: avoid !important;
  }

  .bingo-header {
    display: grid !important;
    grid-template-columns: repeat(5, 1fr) !important;
    margin-bottom: 0 !important;
    gap: 0 !important;
  }

  .bingo-header-cell {
    font-size: 11pt !important;
    color: #000 !important;
    padding: 3px !important;
    font-weight: 700 !important;
    text-align: center !important;
  }

  .bingo-grid {
    display: grid !important;
    grid-template-columns: repeat(5, 1fr) !important;
    border: 2pt solid #000 !important;
    border-radius: 0 !important;
    gap: 0 !important;
  }

  .bingo-cell {
    border: 1pt solid #000 !important;
    font-size: 9pt !important;
    background: white !important;
    color: #000 !important;
    padding: 4px !important;
    height: 55px !important;
    min-height: unset !important;
    aspect-ratio: unset !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    text-align: center !important;
    word-break: break-word !important;
  }

  .bingo-cell.free {
    background: #e5e5e5 !important;
    color: #000 !important;
    font-weight: 700 !important;
  }

  /* ===== FLASHCARDS ===== */
  .flashcards-grid {
    column-count: 2 !important;
    column-gap: 1rem !important;
  }

  .flashcard {
    break-inside: avoid !important;
    page-break-inside: avoid !important;
    border: 1pt solid #000 !important;
    margin-bottom: 0.5rem !important;
    background: white !important;
  }

  /* ===== SUDOKU ===== */
  .sudoku-container {
    border: none !important;
    padding: 0 !important;
    page-break-inside: avoid !important;
  }

  .sudoku-grid {
    margin: 0 auto !important;
  }

  .sudoku-cell {
    background: white !important;
  }

  .sudoku-cell.given {
    background: #f0f0f0 !important;
    font-weight: 700 !important;
  }

  /* ===== WORD LIST ===== */
  .word-list-grid {
    column-count: 3 !important;
    column-gap: 1rem !important;
  }

  .word-list-item {
    break-inside: avoid !important;
    border: 1pt solid #ccc !important;
    background: white !important;
  }

  /* ===== WORD SEARCH ===== */
  .wordsearch-container {
    display: flex !important;
    gap: 8mm !important;
    justify-content: center !important;
    page-break-inside: avoid !important;
  }

  .wordsearch-grid-wrapper {
    flex: 0 0 auto !important;
  }

  .wordsearch-grid {
    background: #000 !important;
    padding: 1px !important;
    border-radius: 0 !important;
    gap: 1px !important;
  }

  .wordsearch-cell {
    background: white !important;
    color: #000 !important;
    font-size: 10pt !important;
    width: 24px !important;
    height: 24px !important;
    font-weight: 500 !important;
  }

  .show-answers .wordsearch-cell.word-letter {
    background: #ddd !important;
    font-weight: 700 !important;
  }

  .wordsearch-wordlist {
    min-width: 150px !important;
    max-width: 200px !important;
  }

  .wordlist-title {
    font-size: 10pt !important;
    color: #000 !important;
    margin-bottom: 3mm !important;
    padding-bottom: 2mm !important;
    border-bottom: 1pt solid #000 !important;
    font-weight: 700 !important;
  }

  .wordlist-items {
    display: grid !important;
    grid-template-columns: 1fr !important;
    gap: 1.5mm !important;
  }

  .wordlist-item {
    padding: 1mm 2mm !important;
    background: white !important;
    border: 1pt solid #ccc !important;
    font-size: 9pt !important;
    color: #000 !important;
  }

  .show-answers .wordlist-item.found {
    background: #ddd !important;
    text-decoration: line-through !important;
  }

  /* ===== VOCABULARY LIST ===== */
  .vocabulary-grid {
    display: grid !important;
    grid-template-columns: repeat(4, 1fr) !important;
    gap: 2mm !important;
  }

  .vocab-item {
    background: white !important;
    border: 1pt solid #ccc !important;
    border-left: 2pt solid #000 !important;
    border-radius: 0 !important;
    padding: 1.5mm 3mm !important;
    font-size: 10pt !important;
  }

  .vocab-item .num {
    color: #000 !important;
    font-size: 9pt !important;
    min-width: 1.5rem !important;
  }

  .vocab-item .word {
    color: #000 !important;
    font-size: 11pt !important;
  }

  /* ===== MATCHING EXERCISE ===== */
  .matching-container {
    display: flex !important;
    gap: 8mm !important;
    justify-content: center !important;
  }

  .matching-column {
    min-width: 180px !important;
    max-width: 220px !important;
  }

  .matching-column h3 {
    font-size: 10pt !important;
    color: #000 !important;
    border-bottom: 1pt solid #000 !important;
    margin-bottom: 3mm !important;
    padding-bottom: 2mm !important;
    font-weight: 700 !important;
  }

  .matching-item {
    padding: 1.5mm 2mm !important;
    margin-bottom: 1.5mm !important;
    font-size: 9pt !important;
    background: white !important;
    border: 1pt solid #ccc !important;
    border-radius: 0 !important;
  }

  .matching-item .num {
    width: 1.2rem !important;
    height: 1.2rem !important;
    line-height: 1.2rem !important;
    font-size: 8pt !important;
    background: white !important;
    color: #000 !important;
    border: 1pt solid #000 !important;
    border-radius: 50% !important;
  }

  /* ===== SPELLING EXERCISE ===== */
  .spelling-grid {
    display: grid !important;
    grid-template-columns: repeat(2, 1fr) !important;
    gap: 2mm !important;
  }

  .spelling-item {
    padding: 1.5mm 3mm !important;
    font-size: 9pt !important;
    background: white !important;
    border: 1pt solid #ccc !important;
  }

  .spelling-item .num {
    color: #000 !important;
    font-size: 8pt !important;
  }

  .spelling-item .scrambled {
    color: #000 !important;
  }

  .spelling-item .blank {
    border-bottom: 1pt solid #000 !important;
    min-width: 3rem !important;
  }

  /* ===== DETAIL ATOM MOUNT (reset container for print) ===== */
  #detail-atom-mount {
    background: white !important;
    border: none !important;
    box-shadow: none !important;
    padding: 0 !important;
    border-radius: 0 !important;
    margin: 0 !important;
  }

  /* ===== CANVAS/SVG PRINT (Maze, Coloring) ===== */
  canvas {
    max-width: 100% !important;
    page-break-inside: avoid !important;
  }

  svg {
    max-width: 100% !important;
    page-break-inside: avoid !important;
  }

  /* ===== PAGE BREAK CONTROL ===== */
  h1, h2, h3 {
    page-break-after: avoid !important;
  }

  table, figure, img {
    page-break-inside: avoid !important;
  }
}

/* ============================================
   Responsive
   ============================================ */

/* ── Tablet (1024px) ── */
@media (max-width: 1024px) {
  .container {
    padding: 0 var(--spacing-md, 1rem);
  }
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.35rem; }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg, 1.5rem);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }

  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }

  .hero {
    padding: var(--spacing-xl) var(--spacing-md);
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  .site-header .container {
    gap: var(--spacing-sm);
  }

  .site-header .logo {
    font-size: 1rem;
  }

  .main-nav ul {
    gap: var(--spacing-sm);
    font-size: 0.875rem;
  }

  .lang-switcher .lang-current {
    padding: 0.25rem 0.5rem;
    font-size: 0.8125rem;
  }

  .lang-switcher .lang-dropdown {
    min-width: 180px;
  }

  .lang-switcher .lang-option {
    padding: 0.5rem 0.75rem;
    font-size: 0.8125rem;
  }

  .page-navigation {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .container {
    padding: 0 var(--spacing-md);
  }

  .category-grid {
    grid-template-columns: 1fr;
  }

  .site-footer nav ul {
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-sm);
  }

  .logo-icon {
    width: 36px;
    height: 36px;
  }

  .logo-text {
    font-size: 1.1rem;
  }

  /* Touch targets - WCAG 2.5.8 */
  button, .btn, [role="button"], .set-btn {
    min-height: 44px;
  }
  .breadcrumb a {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }

  /* Breadcrumb horizontal scroll on mobile */
  .breadcrumb {
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: 0.25rem;
  }
  .breadcrumb::-webkit-scrollbar {
    display: none;
  }
}

/* ── Small phones (320px) ── */
@media (max-width: 320px) {
  h1 { font-size: 1.25rem; }
  .hero { padding: 1rem; }
  .container { padding: 0 0.75rem; }
}

/* ============================================
   Intelligence Panel
   ============================================ */
.intelligence-panel {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  align-items: center;
}

.difficulty-badge,
.suggested-time,
.info-notice {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: 9999px;
  font-size: 0.8125rem;
  font-weight: 600;
  line-height: 1;
  white-space: nowrap;
}

.difficulty-badge svg,
.suggested-time svg,
.info-notice svg {
  flex-shrink: 0;
}

.difficulty-badge[data-level="easy"],
.difficulty-badge[data-level="starter"] {
  background: #dcfce7;
  color: #166534;
}

.difficulty-badge[data-level="medium"] {
  background: #fef3c7;
  color: #92400e;
}

.difficulty-badge[data-level="hard"] {
  background: #fee2e2;
  color: #991b1b;
}

.difficulty-badge[data-level="expert"],
.difficulty-badge[data-level="extreme"] {
  background: #ede9fe;
  color: #5b21b6;
}

.suggested-time {
  background: var(--color-bg-alt);
  color: var(--color-text-light);
  border: 1px solid var(--color-border);
}

.info-notice {
  background: var(--color-bg-alt);
  color: var(--color-text-light);
  border: 1px solid var(--color-border);
}

.badge-score {
  font-size: 0.75rem;
  font-weight: 400;
  opacity: 0.7;
  margin-left: 2px;
}

/* ============================================
   Loading States
   ============================================ */
@keyframes skeleton-pulse {
  0%, 100% { opacity: 0.4; }
  50% { opacity: 0.8; }
}

.sie-mount-point:empty {
  min-height: 200px;
  background: linear-gradient(90deg, var(--color-bg-alt) 25%, var(--color-bg-hover) 50%, var(--color-bg-alt) 75%);
  background-size: 200% 100%;
  border-radius: var(--radius-card);
  animation: skeleton-pulse 1.5s ease-in-out infinite;
}

@media (prefers-reduced-motion: reduce) {
  .sie-mount-point:empty {
    animation: none;
    background: var(--color-bg-alt);
  }
}

/* ============================================
   Platform Utility: Loading Skeleton
   ============================================ */

/* A10: cross-site harmony */
.skeleton {
  background: linear-gradient(90deg, var(--color-bg-alt, #f3f4f6) 25%, var(--color-bg-hover, #e5e7eb) 50%, var(--color-bg-alt, #f3f4f6) 75%);
  background-size: 200% 100%;
  animation: skeletonShimmer 1.5s ease-in-out infinite;
  border-radius: 4px;
}

@keyframes skeletonShimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

@media (prefers-reduced-motion: reduce) {
  .skeleton { animation: none; background: var(--color-bg-alt, #f3f4f6); }
}

/* ============================================
   Platform Utility: Scroll-to-Top Button
   ============================================ */

/* A10: cross-site harmony */
.scroll-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary, #2563eb);
  color: white;
  border: none;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-lg);
  transition: transform var(--dur-fast) var(--ease-default), opacity var(--dur-fast) var(--ease-default);
  z-index: 50;
}

.scroll-to-top:hover { transform: translateY(-3px); }
.scroll-to-top.visible { display: flex; }

@media print { .scroll-to-top { display: none !important; } }

/* ============================================
   Mobile Navigation Toggle
   ============================================ */
.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: none;
  background: none;
  color: var(--color-text);
  cursor: pointer;
  flex-shrink: 0;
  -webkit-tap-highlight-color: transparent;
}

.nav-toggle .nav-toggle-close { display: none; }

.nav-toggle[aria-expanded="true"] .nav-toggle-open { display: none; }
.nav-toggle[aria-expanded="true"] .nav-toggle-close { display: block; }

@media (max-width: 768px) {
  .nav-toggle { display: flex; }

  .main-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    z-index: 99;
  }

  .main-nav.open { display: block; }

  .main-nav ul {
    flex-direction: column;
    gap: 0;
    padding: var(--spacing-sm) 0;
  }

  .main-nav a {
    display: block;
    padding: var(--spacing-md) var(--spacing-lg);
    min-height: 44px;
    line-height: 1.5;
  }

  .main-nav a:hover {
    background: var(--color-bg-hover);
  }
}

/* ============================================
   Entrance Animation
   ============================================ */
.animate-fade-up {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 0.6s ease-out forwards;
}

@keyframes fadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   Dark Mode — DEFERRED
   ============================================ */
/* Dark mode removed (2026-03-19): Educational/print sites must always render in light mode.
   The prefers-color-scheme: dark override was causing input fields and solver cells to
   render as black blocks because --color-bg was set to #111827 but form elements and
   detail-atom components were not fully adapted. Dark mode requires full-chain adaptation
   (detail-atom, site skins, print profiles) before it can be safely enabled.
   See: docs/experts/visual/VISUAL-SYSTEM-AUDIT-V1.md Section 4.3 */

/* ============================================
   Reduced Motion Safety Net
   ============================================ */
@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;
  }
}

/* ============================================
   RTL (Right-to-Left) Comprehensive Support
   Scoped via [dir="rtl"] set on <html> for ar/he.
   Base text-align rule is above in Reset section.
   ============================================ */

/* --- Header & Navigation --- */
[dir="rtl"] .site-header .container {
  flex-direction: row-reverse;
}

[dir="rtl"] .main-nav ul {
  flex-direction: row-reverse;
}

[dir="rtl"] .lang-switcher {
  margin-left: 0;
  margin-right: auto;
}

[dir="rtl"] .lang-switcher .lang-dropdown {
  right: auto;
  left: 0;
}

/* --- Skip Link --- */
[dir="rtl"] .skip-link {
  left: auto;
  right: 0;
}

/* --- Breadcrumb (separator already handled above) --- */
[dir="rtl"] .breadcrumb ol {
  flex-direction: row-reverse;
}

/* --- Page Navigation (prev/next) --- */
[dir="rtl"] .page-navigation {
  flex-direction: row-reverse;
}

/* --- Actions toolbar --- */
[dir="rtl"] .actions {
  flex-direction: row-reverse;
}

/* --- Buttons with icons --- */
[dir="rtl"] .btn {
  flex-direction: row-reverse;
}

/* --- Category & Worksheet Lists --- */
[dir="rtl"] .category-list a,
[dir="rtl"] .worksheet-list a {
  padding: var(--spacing-md) var(--spacing-lg);
  text-align: right;
}

/* --- Footer --- */
[dir="rtl"] .site-footer nav ul {
  flex-direction: row-reverse;
}

/* --- Scroll-to-top button --- */
[dir="rtl"] .scroll-to-top {
  right: auto;
  left: 2rem;
}

/* --- Prose & Content max-width alignment --- */
[dir="rtl"] .prose,
[dir="rtl"] .content-section,
[dir="rtl"] .intro,
[dir="rtl"] .content-toggle-panel,
[dir="rtl"] .body-content {
  margin-left: auto;
  margin-right: 0;
}

/* --- Float direction swap --- */
[dir="rtl"] .float-left {
  float: right;
}

[dir="rtl"] .float-right {
  float: left;
}

/* --- Intelligence panel badge score --- */
[dir="rtl"] .badge-score {
  margin-left: 0;
  margin-right: 0.25rem;
}

/* --- Problem items: mirror left accent border --- */
[dir="rtl"] .problem {
  flex-direction: row-reverse;
}

/* --- Vocabulary items: mirror left accent border --- */
[dir="rtl"] .vocab-item {
  border-left: 1px solid var(--color-border);
  border-right: 2px solid var(--color-primary);
}

/* --- Placeholder pre block alignment --- */
[dir="rtl"] .placeholder pre {
  text-align: right;
  direction: rtl;
}

/* --- Mobile nav panel position --- */
@media (max-width: 768px) {
  [dir="rtl"] .site-header .container {
    flex-direction: row-reverse;
  }

  [dir="rtl"] .main-nav ul {
    flex-direction: column;
  }

  [dir="rtl"] .main-nav a {
    text-align: right;
  }

  [dir="rtl"] .page-navigation {
    flex-direction: column;
  }
}

/* --- Print RTL adjustments --- */
@media print {
  [dir="rtl"] .problem {
    border-left: 1pt solid #bbb !important;
    border-right: 2pt solid #000 !important;
    flex-direction: row-reverse !important;
  }

  [dir="rtl"] .vocab-item {
    border-left: 1pt solid #ccc !important;
    border-right: 2pt solid #000 !important;
  }

  [dir="rtl"] .worksheet-print-meta {
    flex-direction: row-reverse !important;
  }
}


/* ============================================================
   Mobile App Safe Area Support (Capacitor)
   Phase 0.6 — MOBILE-APP-MIGRATION-PLAYBOOK
   ============================================================ */

/* iOS Safe Area padding for notch / Home Indicator */
@supports (padding-top: env(safe-area-inset-top)) {
  .site-header {
    padding-top: env(safe-area-inset-top);
  }

  .main-content {
    padding-bottom: env(safe-area-inset-bottom);
  }

  /* When inside Capacitor App: extra bottom padding for gesture area */
  body.capacitor-app .main-content {
    padding-bottom: calc(env(safe-area-inset-bottom) + 16px);
  }

  /* Hide web-only navigation elements in App context */
  body.capacitor-app .site-header__nav,
  body.capacitor-app .site-footer {
    display: none;
  }

  /* Ensure print is unaffected */
  @media print {
    body.capacitor-app .site-header__nav,
    body.capacitor-app .site-footer {
      display: none;
    }
  }
}

/* Mobile touch optimization (Capacitor context) */
body.capacitor-app {
  -webkit-touch-callout: none;  /* Disable long-press context menu on links */
  -webkit-user-select: none;    /* Prevent accidental text selection */
  user-select: none;
  overscroll-behavior: none;    /* Prevent pull-to-refresh in WebView */
}

/* Re-enable text selection for content areas */
body.capacitor-app .detail-content,
body.capacitor-app .main-content,
body.capacitor-app input,
body.capacitor-app textarea {
  -webkit-user-select: text;
  user-select: text;
}

/* SSR Visual Preview — visible to crawlers but hidden from users */
.seo-visual-preview {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.seo-visual-preview svg {
  max-width: 300px;
  height: auto;
}