:root {
  --color-bg: #ffffff;
  --color-bg-secondary: #f8fafc;
  --color-bg-tertiary: #f1f5f9;
  --color-border: #e2e8f0;
  --color-border-light: #f1f5f9;
  --color-text: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #94a3b8;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #eff6ff;
  --color-python: #3776ab;
  --color-python-light: #fffbeb;
  --color-cpp: #00599c;
  --color-cpp-light: #eff6ff;
  --color-society: #7c3aed;
  --color-society-light: #f5f3ff;
  --color-success: #059669;
  --color-success-light: #ecfdf5;
  --color-warning: #d97706;
  --color-warning-light: #fffbeb;
  --color-danger: #dc2626;
  --color-danger-light: #fef2f2;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-sm: 4px;
  --radius: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, monospace;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg-secondary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

ul, ol {
  list-style: none;
}

img, svg {
  display: block;
  max-width: 100%;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font: inherit;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-brand .logo {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--color-primary);
  border-radius: var(--radius);
  color: white;
}

.nav-brand .brand-text {
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text);
}

.nav-toggle {
  display: none;
  padding: 8px;
  color: var(--color-text-secondary);
}

.nav-toggle:hover {
  color: var(--color-text);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-menu > li > a {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.nav-menu > li > a:hover {
  color: var(--color-text);
  background: var(--color-bg-tertiary);
}

.nav-menu > li > a.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  padding: 8px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: all var(--transition);
}

.dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu > li > a {
  display: block;
  padding: 10px 12px;
  font-size: 14px;
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.dropdown-menu > li > a:hover {
  color: var(--color-text);
  background: var(--color-bg-tertiary);
}

.submenu-item {
  position: relative;
}

.submenu {
  position: absolute;
  left: 100%;
  top: 0;
  min-width: 120px;
  padding: 8px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateX(4px);
  transition: all var(--transition);
}

.submenu-item:hover .submenu {
  opacity: 1;
  visibility: visible;
  transform: translateX(0);
}

.hero {
  margin-top: 64px;
  padding: 80px 24px;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  text-align: center;
}

.hero-content {
  max-width: 640px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 40px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.025em;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: 18px;
  color: var(--color-text-secondary);
  margin-bottom: 32px;
}

.hero-buttons {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 14px;
  font-weight: 500;
  border-radius: var(--radius);
  transition: all var(--transition);
}

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

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

.btn-secondary {
  background: var(--color-bg-tertiary);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

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

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary-light);
}

.features {
  padding: 64px 0;
  background: var(--color-bg);
}

.section-title {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 48px;
  letter-spacing: -0.025em;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  padding: 24px;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}

.feature-card:hover {
  border-color: var(--color-border);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius);
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.course-section {
  padding: 64px 0;
}

.course-section.python-section {
  background: var(--color-python-light);
}

.course-section.cpp-section {
  background: var(--color-cpp-light);
}

.course-section.society-section {
  background: var(--color-society-light);
}

.section-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 32px;
}

.section-header .icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius);
}

.section-header .icon.python {
  background: var(--color-python);
  color: white;
}

.section-header .icon.cpp {
  background: var(--color-cpp);
  color: white;
}

.section-header .icon.society {
  background: var(--color-society);
  color: white;
}

.section-header h2 {
  font-size: 24px;
  font-weight: 700;
}

.grade-tabs {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.grade-group {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
}

.grade-group-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-border-light);
}

.grade-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.grade-card {
  display: flex;
  flex-direction: column;
  padding: 20px;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.grade-card:hover {
  border-color: var(--color-primary);
  background: var(--color-bg);
  box-shadow: var(--shadow);
}

.grade-label {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 4px;
}

.grade-desc {
  font-size: 14px;
  color: var(--color-text-secondary);
}

.footer {
  padding: 32px 0;
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.footer p {
  font-size: 14px;
  color: var(--color-text-secondary);
}

.page-header {
  margin-top: 64px;
  padding: 48px 24px;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  text-align: center;
}

.page-header.python-theme {
  background: var(--color-python);
  color: white;
}

.page-header.cpp-theme {
  background: var(--color-cpp);
  color: white;
}

.page-header.society-theme {
  background: var(--color-society);
  color: white;
}

.page-title {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 8px;
}

.page-subtitle {
  font-size: 16px;
  opacity: 0.9;
}

.mode-switcher {
  position: sticky;
  top: 64px;
  z-index: 100;
  padding: 16px 0;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

.mode-switcher .container {
  display: flex;
  justify-content: center;
  gap: 8px;
}

.mode-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-secondary);
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.mode-btn:hover {
  color: var(--color-text);
  border-color: var(--color-text-muted);
}

.mode-btn.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-color: var(--color-primary);
}

.text-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 48px 24px;
}

.content-section {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
  margin-bottom: 24px;
}

.content-section h2 {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-primary);
}

.content-section h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 24px 0 12px;
}

.content-section p {
  color: var(--color-text-secondary);
  margin-bottom: 16px;
  line-height: 1.7;
}

.content-section ul,
.content-section ol {
  margin: 16px 0;
  padding-left: 24px;
  color: var(--color-text-secondary);
}

.content-section ul {
  list-style: disc;
}

.content-section ol {
  list-style: decimal;
}

.content-section li {
  margin-bottom: 8px;
  line-height: 1.6;
}

.code-block {
  margin: 20px 0;
  background: #1e293b;
  border-radius: var(--radius);
  overflow: hidden;
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px;
  background: #334155;
  border-bottom: 1px solid #475569;
}

.code-lang {
  font-size: 12px;
  font-weight: 500;
  color: #94a3b8;
  text-transform: uppercase;
}

.code-copy {
  padding: 4px 8px;
  font-size: 12px;
  color: #94a3b8;
  background: transparent;
  border: 1px solid #475569;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
}

.code-copy:hover {
  color: white;
  border-color: #64748b;
}

.code-content {
  padding: 20px;
  overflow-x: auto;
}

.code-content pre {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  color: #e2e8f0;
}

.keyword { color: #c084fc; }
.string { color: #86efac; }
.comment { color: #64748b; font-style: italic; }
.function { color: #60a5fa; }
.number { color: #fbbf24; }
.operator { color: #f472b6; }

.tip-box {
  padding: 16px 20px;
  margin: 20px 0;
  border-radius: var(--radius);
  border-left: 4px solid;
}

.tip-box.info {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
}

.tip-box.warning {
  background: var(--color-warning-light);
  border-color: var(--color-warning);
}

.tip-box.success {
  background: var(--color-success-light);
  border-color: var(--color-success);
}

.tip-box-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  margin-bottom: 8px;
}

.tip-box ul {
  margin: 8px 0 0;
  padding-left: 20px;
}

.slideshow-mode {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 2000;
}

.slideshow-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #0f172a;
  z-index: 2000;
  display: flex;
  flex-direction: column;
}

.slideshow-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: #1e293b;
  border-bottom: 1px solid #334155;
}

.slideshow-title {
  font-size: 16px;
  font-weight: 600;
  color: white;
}

.slideshow-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

.slideshow-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  color: white;
  background: #334155;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.slideshow-btn:hover {
  background: #475569;
}

.slideshow-btn.close-btn {
  background: var(--color-danger);
}

.slideshow-btn.close-btn:hover {
  background: #b91c1c;
}

.slide-counter {
  font-size: 14px;
  color: #94a3b8;
  padding: 0 8px;
}

.slideshow-main {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
  overflow: hidden;
}

.slide {
  width: 100%;
  max-width: 1000px;
  background: white;
  border-radius: var(--radius-lg);
  padding: 48px;
  box-shadow: var(--shadow-lg);
  display: none;
  animation: slideIn 0.3s ease;
}

.slide.active {
  display: block;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.slide h2 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-primary);
}

.slide h3 {
  font-size: 20px;
  font-weight: 600;
  margin: 20px 0 12px;
}

.slide p {
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text-secondary);
  margin-bottom: 12px;
}

.slide ul {
  margin-left: 24px;
  list-style: disc;
}

.slide li {
  margin-bottom: 8px;
  color: var(--color-text-secondary);
}

.progress-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  height: 3px;
  background: var(--color-primary);
  transition: width 0.3s ease;
}

.slide-indicator {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 6px;
}

.slide-indicator .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  transition: all var(--transition);
}

.slide-indicator .dot.active {
  background: white;
  width: 24px;
  border-radius: 4px;
}

.society-preview {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 800px;
  margin: 0 auto;
}

.society-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  position: relative;
}

.society-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 4px;
}

.society-card p {
  font-size: 14px;
  color: var(--color-society);
  font-weight: 500;
  margin-bottom: 16px;
}

.society-card ul {
  margin: 16px 0;
  padding-left: 0;
}

.society-card li {
  padding: 8px 0;
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-border-light);
  font-size: 14px;
}

.society-card li:last-child {
  border-bottom: none;
}

.society-card .badge {
  position: absolute;
  top: 16px;
  right: 16px;
  padding: 4px 12px;
  background: var(--color-society);
  color: white;
  border-radius: var(--radius-xl);
  font-size: 12px;
  font-weight: 600;
}

.society-card .card-link {
  display: block;
  text-align: center;
  padding: 12px;
  background: var(--color-society);
  color: white;
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 14px;
  margin-top: 16px;
  transition: all var(--transition);
}

.society-card .card-link:hover {
  opacity: 0.9;
}

.curriculum-table {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 32px;
}

.table-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.table-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-society);
}

.table-card.senior::before {
  background: var(--color-primary);
}

.table-card:hover {
  box-shadow: var(--shadow-md);
}

.table-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 4px;
}

.table-card .subtitle {
  font-size: 14px;
  color: var(--color-society);
  font-weight: 500;
  margin-bottom: 12px;
}

.table-card.senior .subtitle {
  color: var(--color-primary);
}

.topic-list {
  margin: 12px 0;
  padding: 0;
}

.topic-list li {
  padding: 8px 0;
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-border-light);
  font-size: 14px;
}

.topic-list li:last-child {
  border-bottom: none;
}

.lesson-count {
  display: inline-block;
  padding: 6px 12px;
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-xl);
  font-size: 12px;
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-top: 12px;
}

.card-btn {
  display: block;
  text-align: center;
  padding: 10px 16px;
  background: var(--color-society);
  color: white;
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 14px;
  margin-top: 12px;
  transition: all var(--transition);
}

.table-card.senior .card-btn {
  background: var(--color-primary);
}

.card-btn:hover {
  opacity: 0.9;
}

.tips-section {
  padding: 48px 0;
  background: var(--color-bg);
}

.tips-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 32px;
}

.tip-item {
  display: flex;
  gap: 16px;
  padding: 20px;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
}

.tip-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius);
  flex-shrink: 0;
}

.tip-content h4 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 4px;
}

.tip-content p {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.tip-content kbd {
  display: inline-block;
  padding: 2px 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.grade-section {
  margin-bottom: 40px;
  padding: 24px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.grade-title {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 4px;
}

.grade-desc {
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-bottom: 20px;
}

.lesson-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
}

.lesson-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.lesson-card:hover {
  border-color: var(--color-society);
  background: var(--color-society-light);
}

.lesson-num {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--color-society);
  color: white;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 14px;
  flex-shrink: 0;
}

.lesson-title {
  flex: 1;
  font-size: 14px;
  font-weight: 500;
}

.lesson-hours {
  padding: 4px 10px;
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-xl);
  font-size: 12px;
  color: var(--color-text-secondary);
}

.lesson-card.more {
  justify-content: center;
  background: var(--color-society);
  color: white;
  border-color: var(--color-society);
}

.lesson-card.more .lesson-num {
  background: white;
  color: var(--color-society);
}

@media (max-width: 1024px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grade-cards {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .tips-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }
  
  .nav-menu {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    padding: 16px;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    display: none;
  }
  
  .nav-menu.active {
    display: flex;
  }
  
  .nav-menu > li {
    width: 100%;
  }
  
  .nav-menu > li > a {
    display: flex;
    width: 100%;
    padding: 12px;
    border-bottom: 1px solid var(--color-border-light);
  }
  
  .dropdown-menu,
  .submenu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    padding-left: 16px;
    border: none;
    display: none;
  }
  
  .dropdown.active .dropdown-menu {
    display: block;
  }
  
  .hero {
    padding: 48px 24px;
  }
  
  .hero h1 {
    font-size: 28px;
  }
  
  .hero-subtitle {
    font-size: 16px;
  }
  
  .feature-grid {
    grid-template-columns: 1fr;
  }
  
  .grade-cards {
    grid-template-columns: 1fr;
  }
  
  .society-preview {
    grid-template-columns: 1fr;
  }
  
  .tips-grid {
    grid-template-columns: 1fr;
  }
  
  .mode-switcher .container {
    flex-direction: column;
  }
  
  .mode-btn {
    width: 100%;
    justify-content: center;
  }
  
  .content-section {
    padding: 20px;
  }
  
  .slide {
    padding: 24px;
  }
  
  .slideshow-toolbar {
    flex-direction: column;
    gap: 12px;
  }
  
  .slideshow-controls {
    width: 100%;
    justify-content: center;
  }
}

@media print {
  .navbar,
  .mode-switcher,
  .slideshow-mode {
    display: none !important;
  }
  
  .text-content {
    max-width: 100%;
  }
  
  .content-section {
    box-shadow: none;
    border: 1px solid var(--color-border);
  }
}