/*
Theme Name: Belajar Membaca dan Berhitung
Theme URI: https://belajar-membaca-dan-berhitung.virenial.com/
Author: Virenial
Author URI: https://virenial.com/
Description: Theme edukatif anak-anak untuk belajar membaca dan berhitung dengan fitur interaktif, suara, dan filter lengkap. Super SEO, mobile-friendly, dan menyenangkan.
Version: 1.0.0
Requires at least: 6.0
Tested up to: 6.5
Requires PHP: 8.0
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Text Domain: belajar-theme
Tags: education, children, interactive, responsive, accessibility-ready, custom-colors, custom-menu, featured-images, threaded-comments, translation-ready
*/

/* =====================================================
   CSS CUSTOM PROPERTIES
   ===================================================== */
:root {
  /* Colors */
  --color-primary: #FF6B35;
  --color-primary-dark: #E55A26;
  --color-primary-light: #FF8C5A;
  --color-secondary: #4ECDC4;
  --color-secondary-dark: #3AB5AC;
  --color-accent-yellow: #FFE66D;
  --color-accent-purple: #A855F7;
  --color-accent-green: #4ADE80;
  --color-accent-pink: #F472B6;
  --color-accent-blue: #60A5FA;

  --color-bg: #FFFDF7;
  --color-bg-card: #FFFFFF;
  --color-bg-section: #F0FDF4;
  --color-text: #1A1A2E;
  --color-text-muted: #6B7280;
  --color-text-light: #9CA3AF;
  --color-border: #E5E7EB;

  /* Typography */
  --font-display: 'Fredoka One', 'Nunito', cursive;
  --font-body: 'Nunito', 'Poppins', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Border radius */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.14);
  --shadow-card: 0 4px 16px rgba(255,107,53,0.12);

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
  --transition-slow: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Z-index */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal: 300;
  --z-toast: 400;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  overflow-x: hidden;
  min-height: 100vh;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

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

ul, ol { list-style: none; }

button {
  cursor: pointer;
  font-family: var(--font-body);
  border: none;
  background: none;
}

/* =====================================================
   TYPOGRAPHY
   ===================================================== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  line-height: 1.2;
  color: var(--color-text);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.75rem); }
h4 { font-size: 1.25rem; }

p { margin-bottom: var(--space-md); }
p:last-child { margin-bottom: 0; }

/* =====================================================
   LAYOUT
   ===================================================== */
.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-main {
  flex: 1;
}

/* =====================================================
   HEADER
   ===================================================== */
.site-header {
  background: linear-gradient(135deg, var(--color-primary) 0%, #FF8C5A 50%, var(--color-accent-yellow) 100%);
  padding: var(--space-md) 0;
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  box-shadow: 0 4px 24px rgba(255,107,53,0.3);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.site-branding {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  text-decoration: none;
}

.site-logo-icon {
  width: 52px;
  height: 52px;
  background: white;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  flex-shrink: 0;
}

.site-title-wrap .site-name {
  font-family: var(--font-display);
  font-size: 1.4rem;
  color: white;
  display: block;
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.site-title-wrap .site-tagline {
  font-size: 0.75rem;
  color: rgba(255,255,255,0.85);
  display: block;
  margin-top: -2px;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.nav-btn {
  background: rgba(255,255,255,0.2);
  color: white;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-full);
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.875rem;
  backdrop-filter: blur(8px);
  border: 2px solid rgba(255,255,255,0.3);
  transition: all var(--transition-base);
  white-space: nowrap;
}

.nav-btn:hover {
  background: rgba(255,255,255,0.35);
  transform: translateY(-1px);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  background: rgba(255,255,255,0.2);
  border-radius: var(--radius-sm);
  border: 2px solid rgba(255,255,255,0.3);
}

.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: white;
  border-radius: 2px;
  transition: all var(--transition-base);
}

/* =====================================================
   HERO SECTION
   ===================================================== */
.hero-section {
  background: linear-gradient(180deg, #FFF7F0 0%, var(--color-bg) 100%);
  padding: var(--space-2xl) 0 var(--space-xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -20%;
  width: 140%;
  height: 200%;
  background: radial-gradient(ellipse at 30% 40%, rgba(255,107,53,0.08) 0%, transparent 60%),
              radial-gradient(ellipse at 70% 60%, rgba(78,205,196,0.08) 0%, transparent 60%);
  pointer-events: none;
}

.hero-floating-icons {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-bottom: var(--space-lg);
}

.hero-icon {
  width: 56px;
  height: 56px;
  background: white;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  box-shadow: var(--shadow-md);
  animation: float 3s ease-in-out infinite;
}

.hero-icon:nth-child(2) { animation-delay: 0.3s; }
.hero-icon:nth-child(3) { animation-delay: 0.6s; }
.hero-icon:nth-child(4) { animation-delay: 0.9s; }
.hero-icon:nth-child(5) { animation-delay: 1.2s; }

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 6vw, 4rem);
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-md);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto var(--space-lg);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  flex-wrap: wrap;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--color-primary);
  display: block;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* =====================================================
   FILTER SECTION
   ===================================================== */
.filter-section {
  background: white;
  border-bottom: 3px solid var(--color-border);
  position: sticky;
  top: 72px;
  z-index: calc(var(--z-sticky) - 1);
  box-shadow: 0 4px 16px rgba(0,0,0,0.06);
}

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

.filter-row {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
  padding: var(--space-xs) 0;
}

.filter-row + .filter-row {
  border-top: 1px dashed var(--color-border);
  padding-top: var(--space-sm);
  margin-top: var(--space-xs);
}

.filter-label {
  font-weight: 800;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  white-space: nowrap;
  min-width: 80px;
}

.filter-chips {
  display: flex;
  gap: var(--space-xs);
  flex-wrap: wrap;
  flex: 1;
}

.filter-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.35rem 0.85rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 700;
  font-family: var(--font-body);
  border: 2px solid var(--color-border);
  background: white;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
  user-select: none;
}

.filter-chip:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-1px);
  box-shadow: 0 3px 10px rgba(255,107,53,0.2);
}

.filter-chip.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
  box-shadow: 0 3px 12px rgba(255,107,53,0.4);
  transform: translateY(-1px);
}

.filter-chip[data-cat="huruf"].active { background: var(--color-accent-purple); border-color: var(--color-accent-purple); }
.filter-chip[data-cat="membaca"].active { background: var(--color-secondary); border-color: var(--color-secondary); }
.filter-chip[data-cat="hewan"].active { background: var(--color-accent-green); border-color: var(--color-accent-green); color: #166534; }
.filter-chip[data-cat="kendaraan"].active { background: var(--color-accent-blue); border-color: var(--color-accent-blue); }
.filter-chip[data-cat="buah"].active { background: var(--color-accent-pink); border-color: var(--color-accent-pink); }
.filter-chip[data-lang="en"].active { background: #3B82F6; border-color: #3B82F6; }
.filter-chip[data-case="besar"].active { background: var(--color-text); border-color: var(--color-text); }

.filter-search {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: 0.35rem 0.85rem;
  transition: all var(--transition-base);
}

.filter-search:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(255,107,53,0.1);
}

.filter-search input {
  border: none;
  background: none;
  font-family: var(--font-body);
  font-size: 0.85rem;
  color: var(--color-text);
  outline: none;
  width: 160px;
}

.filter-search input::placeholder { color: var(--color-text-light); }

.filter-clear {
  padding: 0.35rem 1rem;
  border-radius: var(--radius-full);
  background: #FEE2E2;
  color: #DC2626;
  font-size: 0.8rem;
  font-weight: 700;
  border: 2px solid #FCA5A5;
  cursor: pointer;
  transition: all var(--transition-base);
}

.filter-clear:hover {
  background: #DC2626;
  color: white;
  border-color: #DC2626;
}

/* =====================================================
   LEARNING GRID
   ===================================================== */
.learning-section {
  padding: var(--space-xl) 0 var(--space-3xl);
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.section-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.item-count {
  background: var(--color-primary);
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: var(--radius-full);
  vertical-align: middle;
}

.sort-select {
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-full);
  border: 2px solid var(--color-border);
  font-family: var(--font-body);
  font-size: 0.8rem;
  color: var(--color-text-muted);
  background: white;
  cursor: pointer;
  outline: none;
}

.learning-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: var(--space-md);
}

/* =====================================================
   LEARNING CARD
   ===================================================== */
.learning-card {
  background: white;
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-slow);
  border: 3px solid var(--color-border);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  box-shadow: var(--shadow-sm);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.learning-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 60%, rgba(255,107,53,0.04));
  pointer-events: none;
}

.learning-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.learning-card.playing {
  animation: cardPulse 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(255,107,53,0.2), var(--shadow-lg);
}

@keyframes cardPulse {
  0% { transform: scale(1); }
  40% { transform: scale(1.08) rotate(-2deg); }
  70% { transform: scale(1.05) rotate(1deg); }
  100% { transform: scale(1); }
}

.card-emoji {
  font-size: 3.5rem;
  line-height: 1;
  display: block;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.1));
  transition: transform var(--transition-base);
}

.learning-card:hover .card-emoji {
  transform: scale(1.1) rotate(-5deg);
}

.card-character {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--color-primary);
  line-height: 1;
  min-height: 3rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card-character.uppercase { text-transform: uppercase; }
.card-character.lowercase { text-transform: lowercase; }

.card-name {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
}

.card-translation {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  font-style: italic;
}

.card-badge {
  position: absolute;
  top: 8px;
  right: 8px;
  background: var(--color-accent-yellow);
  color: var(--color-text);
  font-size: 0.6rem;
  font-weight: 800;
  padding: 2px 6px;
  border-radius: var(--radius-full);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.card-sound-indicator {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 0.875rem;
  opacity: 0;
  transform: scale(0.5);
  transition: all var(--transition-base);
}

.learning-card:hover .card-sound-indicator,
.learning-card.playing .card-sound-indicator {
  opacity: 1;
  transform: scale(1);
}

/* Category color coding */
.learning-card[data-cat="angka"] { border-top: 4px solid var(--color-primary); }
.learning-card[data-cat="huruf"] { border-top: 4px solid var(--color-accent-purple); }
.learning-card[data-cat="membaca"] { border-top: 4px solid var(--color-secondary); }
.learning-card[data-cat="hewan"] { border-top: 4px solid var(--color-accent-green); }
.learning-card[data-cat="kendaraan"] { border-top: 4px solid var(--color-accent-blue); }
.learning-card[data-cat="buah"] { border-top: 4px solid var(--color-accent-pink); }
.learning-card[data-cat="lainnya"] { border-top: 4px solid var(--color-accent-yellow); }

/* =====================================================
   NO RESULTS
   ===================================================== */
.no-results {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--space-3xl) var(--space-xl);
  color: var(--color-text-muted);
}

.no-results-emoji {
  font-size: 4rem;
  display: block;
  margin-bottom: var(--space-md);
  animation: bounce 2s ease infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

/* =====================================================
   SOUND PROGRESS BAR
   ===================================================== */
.sound-progress {
  position: fixed;
  bottom: 0;
  left: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  width: 0;
  z-index: var(--z-toast);
  transition: width 0.1s linear;
  box-shadow: 0 -2px 8px rgba(255,107,53,0.4);
}

/* =====================================================
   TOAST NOTIFICATION
   ===================================================== */
.toast {
  position: fixed;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-text);
  color: white;
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 0.875rem;
  z-index: var(--z-toast);
  transition: transform var(--transition-slow);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  box-shadow: var(--shadow-lg);
  pointer-events: none;
  white-space: nowrap;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
}

/* =====================================================
   CONFETTI / REWARD
   ===================================================== */
.confetti-container {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: var(--z-modal);
  overflow: hidden;
}

.confetti-piece {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 2px;
  animation: confettiFall 3s ease-in forwards;
}

@keyframes confettiFall {
  0% { transform: translateY(-20px) rotate(0deg); opacity: 1; }
  100% { transform: translateY(100vh) rotate(720deg); opacity: 0; }
}

/* =====================================================
   CATEGORIES OVERVIEW
   ===================================================== */
.categories-section {
  background: linear-gradient(135deg, #F0FDF4, #EFF6FF);
  padding: var(--space-2xl) 0;
  border-top: 3px dashed var(--color-border);
  border-bottom: 3px dashed var(--color-border);
}

.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: var(--space-md);
  margin-top: var(--space-xl);
}

.category-card {
  background: white;
  border-radius: var(--radius-lg);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-slow);
  border: 2px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.category-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.category-icon {
  font-size: 2.5rem;
  display: block;
  margin-bottom: var(--space-sm);
}

.category-name {
  font-family: var(--font-display);
  font-size: 0.95rem;
  color: var(--color-text);
}

.category-count {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-top: 2px;
}

/* =====================================================
   HOW TO USE
   ===================================================== */
.how-section {
  padding: var(--space-2xl) 0;
}

.how-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--space-lg);
  margin-top: var(--space-xl);
}

.how-card {
  background: white;
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border: 2px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.how-step {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.25rem;
  flex-shrink: 0;
}

.how-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  color: var(--color-text);
}

.how-desc {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: 0;
}

/* =====================================================
   FOOTER
   ===================================================== */
.site-footer {
  background: linear-gradient(135deg, var(--color-text) 0%, #2D2D44 100%);
  color: rgba(255,255,255,0.8);
  padding: var(--space-2xl) 0 var(--space-md);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

.footer-brand .site-name {
  font-family: var(--font-display);
  font-size: 1.4rem;
  color: white;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.footer-brand p {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.6);
}

.footer-title {
  font-family: var(--font-display);
  font-size: 1rem;
  color: white;
  margin-bottom: var(--space-md);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.footer-links a {
  color: rgba(255,255,255,0.6);
  font-size: 0.875rem;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-sm);
  font-size: 0.8rem;
  color: rgba(255,255,255,0.5);
}

/* =====================================================
   BACK TO TOP
   ===================================================== */
.back-to-top {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: var(--shadow-md);
  z-index: var(--z-sticky);
  opacity: 0;
  transform: translateY(20px);
  transition: all var(--transition-base);
}

.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
}

/* =====================================================
   LOADING SKELETON
   ===================================================== */
.skeleton {
  background: linear-gradient(90deg, #f0f0f0 25%, #e8e8e8 50%, #f0f0f0 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-md);
}

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

/* =====================================================
   ACCESSIBILITY
   ===================================================== */
:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border-width: 0;
}

/* =====================================================
   PRINT STYLES
   ===================================================== */
@media print {
  .site-header, .filter-section, .back-to-top, .toast { display: none; }
  .learning-card { break-inside: avoid; }
}

/* =====================================================
   RESPONSIVE
   ===================================================== */
@media (max-width: 768px) {
  .hamburger { display: flex; }
  .header-nav { display: none; }
  .header-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-primary);
    padding: var(--space-md);
    box-shadow: var(--shadow-lg);
  }

  .hero-section { padding: var(--space-xl) 0 var(--space-lg); }
  .hero-floating-icons { gap: var(--space-sm); }
  .hero-icon { width: 44px; height: 44px; font-size: 1.4rem; }
  .hero-stats { gap: var(--space-lg); }

  .filter-section { top: 60px; }
  .filter-label { min-width: 60px; font-size: 0.65rem; }
  .filter-chip { font-size: 0.72rem; padding: 0.28rem 0.65rem; }
  .filter-search input { width: 120px; }

  .learning-grid { grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); gap: var(--space-sm); }
  .card-emoji { font-size: 2.8rem; }
  .card-character { font-size: 2rem; }

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

  .back-to-top { bottom: var(--space-md); right: var(--space-md); }
}

@media (max-width: 480px) {
  .site-logo-icon { width: 42px; height: 42px; font-size: 1.4rem; }
  .site-title-wrap .site-name { font-size: 1.1rem; }
  .filter-row { gap: var(--space-xs); }
  .learning-grid { grid-template-columns: repeat(auto-fill, minmax(110px, 1fr)); }
  .footer-grid { grid-template-columns: 1fr; }
}

/* =====================================================
   DARK MODE SUPPORT
   ===================================================== */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0F0F1A;
    --color-bg-card: #1A1A2E;
    --color-bg-section: #161625;
    --color-text: #F5F5F5;
    --color-text-muted: #9CA3AF;
    --color-border: #2D2D44;
  }

  .filter-section { background: var(--color-bg-card); }
  .learning-card { background: var(--color-bg-card); }
  .category-card, .how-card { background: var(--color-bg-card); }
  .filter-chip { background: var(--color-bg-card); }
  .filter-search { background: var(--color-bg); }
  .site-header { box-shadow: 0 4px 24px rgba(0,0,0,0.5); }
}

/* =====================================================
   ANIMATION HELPERS
   ===================================================== */
.animate-in {
  animation: slideUp 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

.fade-out {
  animation: fadeOut 0.2s ease forwards;
}

@keyframes fadeOut {
  to { opacity: 0; transform: scale(0.9); }
}