/* =============================================
   smerchbn.com - Online English Learning
   Main Stylesheet v2.0 — Modern UI Redesign
   ============================================= */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500&display=swap');

/* --- CSS Variables --- */
:root {
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --primary-light: #e0e7ff;
  --primary-glow: rgba(79, 70, 229, 0.25);
  --secondary: #10b981;
  --secondary-dark: #059669;
  --secondary-light: #d1fae5;
  --accent: #f59e0b;
  --accent-light: #fef3c7;
  --dark: #0f172a;
  --dark-soft: #1e293b;
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --white: #ffffff;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.04);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.1), 0 4px 16px rgba(0,0,0,0.06);
  --shadow-xl: 0 20px 48px rgba(0,0,0,0.12), 0 8px 24px rgba(0,0,0,0.08);
  --radius: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1200px;
  --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

body {
  font-family: var(--font-sans);
  color: var(--dark);
  background: var(--gray-50);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

body,
p,
li,
td,
th,
a,
span,
div {
  overflow-wrap: anywhere;
  word-break: normal;
}

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

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

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

ul, ol {
  padding-left: 1.25rem;
}

::selection {
  background: var(--primary-light);
  color: var(--primary-dark);
}

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* --- Header --- */
.site-header {
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0,0,0,0.06);
  position: sticky;
  top: 0;
  z-index: 100;
  transition: box-shadow var(--transition);
}

.site-header:hover,
.site-header.scrolled {
  box-shadow: 0 4px 20px rgba(0,0,0,0.06);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.logo {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  letter-spacing: -0.02em;
}

.logo:hover {
  color: var(--primary-dark);
  transform: scale(1.02);
}

.logo .logo-icon {
  font-size: 1.6rem;
}

/* --- Navigation --- */
.main-nav {
  display: flex;
  align-items: center;
  gap: 0.15rem;
}

.main-nav a {
  color: var(--gray-600);
  padding: 0.5rem 0.8rem;
  border-radius: var(--radius);
  font-size: 0.88rem;
  font-weight: 500;
  transition: all var(--transition);
  position: relative;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--primary);
  background: var(--primary-light);
}

.main-nav a.active::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 2px;
  background: var(--primary);
  border-radius: 2px;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--gray-600);
  padding: 0.25rem;
  border-radius: var(--radius);
  transition: all var(--transition);
}

.nav-toggle:hover {
  background: var(--gray-100);
  color: var(--dark);
}

/* --- Hero Section --- */
.hero {
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 50%, #a855f7 100%);
  color: var(--white);
  padding: 5rem 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: rgba(255,255,255,0.05);
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: rgba(255,255,255,0.03);
  pointer-events: none;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 900;
  margin-bottom: 1rem;
  line-height: 1.15;
  letter-spacing: -0.03em;
  position: relative;
  z-index: 1;
}

.hero p {
  font-size: 1.15rem;
  opacity: 0.9;
  max-width: 640px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
  position: relative;
  z-index: 1;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.8rem 1.75rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  font-family: var(--font-sans);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--white);
  color: var(--primary);
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.btn-primary:hover {
  background: var(--gray-50);
  color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.15);
}

.btn-secondary {
  background: transparent;
  color: var(--white);
  border: 2px solid rgba(255,255,255,0.4);
}

.btn-secondary:hover {
  border-color: var(--white);
  background: rgba(255,255,255,0.15);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover {
  background: var(--primary);
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px var(--primary-glow);
}

.btn-sm {
  padding: 0.45rem 1.1rem;
  font-size: 0.85rem;
}

/* --- Sections --- */
.section {
  padding: 4rem 0;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--dark);
  margin-bottom: 0.5rem;
  text-align: center;
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--gray-500);
  text-align: center;
  margin-bottom: 3rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.6;
}

.section-light {
  background: var(--white);
}

.section-gray {
  background: var(--gray-100);
}

/* --- Cards --- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), #7c3aed);
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.card:hover::before {
  opacity: 1;
}

.card-icon {
  font-size: 2.2rem;
  margin-bottom: 0.75rem;
  display: block;
}

.card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--dark);
  letter-spacing: -0.01em;
}

.card p {
  font-size: 0.92rem;
  color: var(--gray-500);
  line-height: 1.6;
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  margin-top: 0.85rem;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--primary);
  transition: all var(--transition);
}

.card-link::after {
  content: '\2192';
  transition: transform var(--transition);
}

.card-link:hover::after {
  transform: translateX(4px);
}

.card-link:hover {
  color: var(--primary-dark);
}

/* --- Breadcrumbs --- */
.breadcrumbs {
  background: var(--gray-50);
  padding: 0.85rem 0;
  font-size: 0.85rem;
  border-bottom: 1px solid var(--gray-100);
}

.breadcrumbs ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.breadcrumbs li:not(:last-child)::after {
  content: '/';
  color: var(--gray-300);
  margin-left: 0.5rem;
}

.breadcrumbs a {
  color: var(--gray-400);
  transition: color var(--transition);
}

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

.breadcrumbs .current {
  color: var(--gray-700);
  font-weight: 500;
}

/* --- Page Header --- */
.page-header {
  background: linear-gradient(135deg, var(--dark) 0%, #334155 50%, var(--dark-soft) 100%);
  color: var(--white);
  padding: 3.5rem 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -15%;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: rgba(79, 70, 229, 0.08);
  pointer-events: none;
}

.page-header h1 {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
  position: relative;
}

.page-header p {
  font-size: 1.05rem;
  opacity: 0.85;
  max-width: 600px;
  margin: 0 auto;
  position: relative;
  line-height: 1.6;
}

/* --- Content Layout --- */
.content-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 2rem;
  max-width: var(--max-width);
  margin: 2rem auto;
  padding: 0 1.5rem;
}

.content-main {
  min-width: 0;
}

.content-sidebar {
  position: sticky;
  top: 84px;
  align-self: start;
}

/* --- Sidebar Widgets --- */
.sidebar-widget {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.sidebar-widget h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.85rem;
  padding-bottom: 0.65rem;
  border-bottom: 2px solid var(--primary-light);
  color: var(--dark);
}

.sidebar-widget ul {
  list-style: none;
  padding: 0;
}

.sidebar-widget li {
  padding: 0.4rem 0;
}

.sidebar-widget li a {
  font-size: 0.9rem;
  color: var(--gray-500);
  transition: all var(--transition);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.sidebar-widget li a::before {
  content: '\203A';
  color: var(--gray-300);
  font-weight: 700;
  transition: color var(--transition);
}

.sidebar-widget li a:hover {
  color: var(--primary);
  padding-left: 4px;
}

.sidebar-widget li a:hover::before {
  color: var(--primary);
}

/* --- Article / Lesson Content --- */
.lesson-content h2 {
  font-size: 1.6rem;
  font-weight: 800;
  margin: 2.5rem 0 0.75rem;
  color: var(--dark);
  letter-spacing: -0.01em;
  position: relative;
  padding-left: 1rem;
}

.lesson-content h2::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.15em;
  bottom: 0.15em;
  width: 4px;
  background: linear-gradient(180deg, var(--primary), #7c3aed);
  border-radius: 4px;
}

.lesson-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin: 1.75rem 0 0.5rem;
  color: var(--dark);
}

.lesson-content p {
  margin-bottom: 1rem;
  color: var(--gray-700);
  line-height: 1.8;
}

.lesson-content ul,
.lesson-content ol {
  margin-bottom: 1rem;
}

.lesson-content li {
  margin-bottom: 0.4rem;
  color: var(--gray-700);
}

/* --- Examples / Highlight Boxes --- */
.example-box {
  background: linear-gradient(135deg, var(--primary-light) 0%, #ede9fe 100%);
  border-left: 4px solid var(--primary);
  padding: 1.15rem 1.5rem;
  margin: 1.25rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: var(--shadow-sm);
}

.example-box strong {
  color: var(--primary-dark);
}

.example-box .en {
  display: block;
  color: var(--dark);
  font-weight: 500;
}

.example-box .zh {
  display: block;
  color: var(--gray-500);
  font-size: 0.9rem;
  margin-top: 0.25rem;
  font-style: italic;
}

.tip-box {
  background: linear-gradient(135deg, var(--accent-light) 0%, #fff7ed 100%);
  border-left: 4px solid var(--accent);
  padding: 1.15rem 1.5rem;
  margin: 1.25rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: var(--shadow-sm);
}

.warning-box {
  background: linear-gradient(135deg, #fee2e2 0%, #fff1f2 100%);
  border-left: 4px solid #ef4444;
  padding: 1.15rem 1.5rem;
  margin: 1.25rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: var(--shadow-sm);
}

.success-box {
  background: linear-gradient(135deg, var(--secondary-light) 0%, #ecfdf5 100%);
  border-left: 4px solid var(--secondary);
  padding: 1.15rem 1.5rem;
  margin: 1.25rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: var(--shadow-sm);
}

/* --- Tables --- */
.content-table {
  width: 100%;
  max-width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  table-layout: auto;
}

.content-table th,
.content-table td {
  padding: 0.85rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--gray-200);
}

.content-table th {
  background: var(--gray-100);
  font-weight: 600;
  color: var(--gray-700);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.content-table tr:hover {
  background: var(--gray-50);
}

/* --- Quiz / Exercise Styles --- */
.quiz-question {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1rem;
  box-shadow: var(--shadow-sm);
}

.quiz-question .q-label {
  font-weight: 700;
  color: var(--primary);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.quiz-question .q-text {
  font-size: 1.05rem;
  margin-bottom: 0.85rem;
  color: var(--dark);
  font-weight: 500;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.quiz-option {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem 1rem;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  font-size: 0.92rem;
}

.quiz-option:hover {
  background: var(--primary-light);
  border-color: var(--primary-light);
}

.quiz-option input[type="radio"] {
  accent-color: var(--primary);
}

.quiz-option.correct {
  background: var(--secondary-light);
  border-color: var(--secondary);
}

.quiz-option.incorrect {
  background: #fee2e2;
  border-color: #ef4444;
}

.quiz-feedback {
  margin-top: 0.75rem;
  padding: 0.85rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  display: none;
}

.quiz-feedback.show {
  display: block;
}

.quiz-feedback.correct {
  background: var(--secondary-light);
  color: #065f46;
}

.quiz-feedback.incorrect {
  background: #fee2e2;
  color: #991b1b;
}

/* --- Progress Bar --- */
.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--gray-200);
  border-radius: 4px;
  overflow: hidden;
  margin: 0.5rem 0;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), #7c3aed);
  border-radius: 4px;
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Vocabulary List --- */
.vocab-search {
  width: 100%;
  padding: 0.85rem 1.15rem;
  border: 2px solid var(--gray-200);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: var(--font-sans);
  margin-bottom: 1rem;
  transition: all var(--transition);
  background: var(--white);
}

.vocab-search:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px var(--primary-glow);
}

.vocab-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr) minmax(0, 1fr);
  gap: 0.75rem;
  padding: 0.85rem;
  border-bottom: 1px solid var(--gray-200);
  align-items: center;
  transition: background var(--transition);
  min-width: 0;
}

.vocab-item:hover {
  background: var(--gray-50);
}

.vocab-item .word {
  font-weight: 700;
  color: var(--dark);
}

.vocab-item .definition {
  color: var(--gray-600);
  font-size: 0.9rem;
}

.vocab-item .tag {
  font-size: 0.75rem;
  padding: 0.25rem 0.6rem;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 6px;
  text-align: center;
  font-weight: 600;
}

/* --- Blog --- */
.blog-list {
  display: grid;
  gap: 1.5rem;
}

.blog-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.blog-card:hover {
  box-shadow: var(--shadow-lg);
  border-color: transparent;
  transform: translateY(-2px);
}

.blog-card .blog-meta {
  font-size: 0.8rem;
  color: var(--gray-400);
  margin-bottom: 0.5rem;
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.blog-card .blog-meta::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  background: var(--primary);
  border-radius: 50%;
}

.blog-card h2 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.blog-card h2 a {
  color: var(--dark);
  transition: color var(--transition);
}

.blog-card h2 a:hover {
  color: var(--primary);
}

.blog-card .blog-excerpt {
  font-size: 0.92rem;
  color: var(--gray-500);
  line-height: 1.7;
}

/* --- Footer --- */
.site-footer {
  background: var(--dark);
  color: var(--gray-400);
  padding: 4rem 0 1.5rem;
  margin-top: auto;
  position: relative;
}

.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), #7c3aed, var(--secondary));
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2.5rem;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.footer-col h4 {
  color: var(--white);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 1.15rem;
  letter-spacing: 0.01em;
}

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

.footer-col li {
  margin-bottom: 0.55rem;
}

.footer-col a {
  color: var(--gray-400);
  font-size: 0.88rem;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.footer-col a:hover {
  color: var(--white);
  transform: translateX(3px);
}

.footer-bottom {
  border-top: 1px solid var(--gray-700);
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  text-align: center;
  font-size: 0.85rem;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* --- AdSense Placeholders --- */
.ad-placeholder {
  background: var(--gray-100);
  border: 1px dashed var(--gray-300);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
  color: var(--gray-400);
  font-size: 0.85rem;
  margin: 1rem 0;
}

/* --- Page Content --- */
.page-content {
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

.page-content h2 {
  font-size: 1.6rem;
  font-weight: 800;
  margin: 2.5rem 0 0.75rem;
  letter-spacing: -0.01em;
}

.page-content p {
  margin-bottom: 1rem;
  color: var(--gray-700);
  line-height: 1.8;
}

/* --- Contact Form --- */
.contact-form {
  max-width: 600px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.4rem;
  color: var(--gray-700);
  font-size: 0.9rem;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.75rem 0.85rem;
  border: 2px solid var(--gray-200);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: var(--font-sans);
  transition: all var(--transition);
  background: var(--white);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px var(--primary-glow);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

/* --- Pagination --- */
.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin: 2.5rem 0;
}

.pagination a {
  padding: 0.55rem 0.85rem;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  color: var(--gray-600);
  font-size: 0.9rem;
  transition: all var(--transition);
  font-weight: 500;
}

.pagination a:hover,
.pagination a.active {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
  box-shadow: 0 2px 8px var(--primary-glow);
}

/* --- Stats / Counters --- */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1.5rem;
  text-align: center;
}

.stat-item {
  padding: 2rem 1rem;
  border-radius: var(--radius-lg);
  transition: transform var(--transition);
}

.stat-item:hover {
  transform: translateY(-3px);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--primary), #7c3aed);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.stat-label {
  font-size: 0.88rem;
  color: var(--gray-500);
  margin-top: 0.3rem;
  font-weight: 500;
}

/* --- Back to Top --- */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: var(--white);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.25rem;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px var(--primary-glow);
  transition: all var(--transition);
  z-index: 90;
}

.back-to-top:hover {
  background: var(--primary-dark);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px var(--primary-glow);
}

.back-to-top.show {
  display: flex;
}

/* --- Social Share Button --- */
.share-section {
  margin: 2rem 0;
  padding: 1.25rem;
  background: var(--gray-50);
  border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.share-section .share-label {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--gray-600);
}

.share-btn-facebook {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 1.2rem;
  background: #1877f2;
  color: var(--white);
  border: none;
  border-radius: var(--radius);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  font-family: var(--font-sans);
}

.share-btn-facebook:hover {
  background: #166fe5;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(24,119,242,0.35);
  color: var(--white);
}

.share-btn-facebook svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .main-nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--gray-200);
    box-shadow: var(--shadow-lg);
    z-index: 99;
  }

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

  .main-nav a {
    width: 100%;
    padding: 0.75rem;
  }

  .hero {
    padding: 3rem 0;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .content-layout {
    grid-template-columns: minmax(0, 1fr);
    padding: 0 1rem;
  }

  .content-sidebar {
    position: static;
  }

  .section {
    padding: 2.5rem 0;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .page-header {
    padding: 2.5rem 0;
  }

  .page-header h1 {
    font-size: 1.75rem;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
  }

  .vocab-item {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .vocab-header {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr) !important;
  }

  .vocab-header span:nth-child(3),
  .vocab-item .tag {
    grid-column: 1 / -1;
    justify-self: start;
  }

  .content-table {
    display: block;
    width: 100%;
    max-width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    white-space: nowrap;
  }

  .content-table th,
  .content-table td {
    padding: 0.65rem 0.75rem;
    min-width: 110px;
  }

  .content-table th:first-child,
  .content-table td:first-child {
    min-width: 90px;
  }

  .stat-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .stat-number {
    font-size: 2rem;
  }

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

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

  .main-nav {
    max-height: calc(100vh - 68px);
    overflow-y: auto;
  }

  .logo {
    min-width: 0;
    font-size: 1.05rem;
  }

  .logo span:last-child {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .hero h1 {
    font-size: 1.65rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .blog-list {
    gap: 1rem;
  }

  .container {
    padding: 0 1rem;
    max-width: 100%;
  }

  .page-content,
  .content-layout {
    padding-left: 1rem;
    padding-right: 1rem;
    max-width: 100%;
  }

  .header-inner {
    padding: 0 1rem;
  }

  .stat-grid {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .vocab-header,
  .vocab-item {
    grid-template-columns: 1fr !important;
    gap: 0.35rem;
  }

  .vocab-header span:nth-child(2),
  .vocab-header span:nth-child(3) {
    display: none;
  }

  .vocab-item .tag {
    grid-column: auto;
    width: fit-content;
  }

  .share-section {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
    padding: 1rem;
  }

  .share-section .share-label {
    text-align: center;
  }

  .share-btn-facebook {
    width: 100%;
    justify-content: center;
    min-width: 0;
  }

  .breadcrumbs ol {
    gap: 0.25rem;
  }

  .breadcrumbs li,
  .breadcrumbs a {
    font-size: 0.78rem;
  }

  .btn {
    width: 100%;
    justify-content: center;
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .hero-actions .btn {
    max-width: 280px;
  }

  .stat-item {
    padding: 1.25rem 0.5rem;
  }

  .stat-number {
    font-size: 1.75rem;
  }
}