/* NEO Regex Guide - Common Guide Styles */

/* =========================
   Guide Header
   ========================= */
.guide-header {
  padding: 8rem 0 4rem;
  background: linear-gradient(135deg, 
    rgba(16, 185, 129, 0.05) 0%, 
    rgba(99, 102, 241, 0.05) 50%, 
    rgba(245, 158, 11, 0.05) 100%);
  border-bottom: 1px solid var(--color-gray-200);
  position: relative;
  overflow: hidden;
}

.guide-header.beginner {
  background: linear-gradient(135deg, 
    rgba(16, 185, 129, 0.1) 0%, 
    rgba(34, 197, 94, 0.05) 50%, 
    rgba(168, 85, 247, 0.05) 100%);
}

.guide-header::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: 
    radial-gradient(circle at 25% 25%, rgba(16, 185, 129, 0.05) 0%, transparent 50%),
    radial-gradient(circle at 75% 75%, rgba(99, 102, 241, 0.05) 0%, transparent 50%);
  animation: float 20s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: rotate(0deg) scale(1); }
  50% { transform: rotate(180deg) scale(1.1); }
}

.header-content {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.header-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: rgba(16, 185, 129, 0.1);
  color: var(--color-success-700);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-4);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

.header-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-gray-900);
  margin-bottom: var(--space-4);
  background: linear-gradient(135deg, var(--color-success-600), var(--color-primary-600));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

@media (min-width: 640px) {
  .header-title {
    font-size: 3rem;
  }
}

.header-subtitle {
  font-size: 1.125rem;
  color: var(--color-gray-600);
  line-height: 1.6;
  margin-bottom: var(--space-8);
}

/* Progress Bar */
.progress-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  max-width: 400px;
  margin: 0 auto;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--color-gray-200);
  border-radius: var(--radius-full);
  overflow: hidden;
  position: relative;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-success-500), var(--color-success-600));
  border-radius: var(--radius-full);
  width: 14.28%; /* 1/7 lessons */
  transition: width 0.5s ease-out;
  position: relative;
}

.progress-fill::after {
  content: '';
  position: absolute;
  top: 0;
  right: -10px;
  width: 20px;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  animation: shine 2s infinite;
}

@keyframes shine {
  0% { transform: translateX(-20px); }
  100% { transform: translateX(20px); }
}

.progress-text {
  font-size: 0.875rem;
  color: var(--color-gray-600);
  font-weight: 500;
}

/* =========================
   Table of Contents
   ========================= */
.toc-section {
  padding: var(--space-8) 0;
  background: white;
}

.toc-card {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-2xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-lg);
}

.toc-title {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-gray-900);
  margin-bottom: var(--space-6);
  text-align: center;
  justify-content: center;
}

.toc-title i {
  color: var(--color-success-600);
}

.toc-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

@media (min-width: 768px) {
  .toc-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .toc-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.toc-item {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--color-gray-50);
  border: 2px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: var(--color-gray-700);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.toc-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(16, 185, 129, 0.1), transparent);
  transition: left 0.5s ease;
}

.toc-item:hover::before {
  left: 100%;
}

.toc-item:hover,
.toc-item.active {
  border-color: var(--color-success-400);
  background: var(--color-success-50);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.toc-item.completed {
  border-color: var(--color-success-500);
  background: var(--color-success-100);
}

.toc-number {
  width: 3rem;
  height: 3rem;
  background: var(--color-gray-300);
  color: var(--color-gray-700);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.125rem;
  flex-shrink: 0;
  transition: all var(--transition-normal);
}

.toc-item.active .toc-number {
  background: var(--color-success-500);
  color: white;
}

.toc-item.completed .toc-number {
  background: var(--color-success-600);
  color: white;
}

.toc-content {
  flex: 1;
}

.toc-content h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-1);
}

.toc-content p {
  font-size: 0.875rem;
  color: var(--color-gray-600);
  line-height: 1.4;
}

.toc-check {
  color: var(--color-gray-400);
  opacity: 0;
  transition: all var(--transition-normal);
}

.toc-item.completed .toc-check {
  color: var(--color-success-500);
  opacity: 1;
}

/* =========================
   Lesson Container
   ========================= */
.guide-main {
  padding: var(--space-8) 0;
  background: var(--color-gray-50);
}

.lesson-container {
  max-width: 800px;
  margin: 0 auto;
}

.lesson {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-2xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-lg);
  display: none;
  animation: fadeInUp 0.5s ease-out;
}

.lesson.active {
  display: block;
}

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

.lesson-header {
  text-align: center;
  margin-bottom: var(--space-8);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-gray-200);
}

.lesson-badge {
  display: inline-block;
  background: var(--color-success-100);
  color: var(--color-success-700);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
}

.lesson-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-gray-900);
  margin-bottom: var(--space-3);
}

.lesson-subtitle {
  font-size: 1.125rem;
  color: var(--color-gray-600);
  line-height: 1.6;
}

/* =========================
   Lesson Content
   ========================= */
.lesson-content {
  margin-bottom: var(--space-8);
}

.content-section {
  margin-bottom: var(--space-8);
}

.content-section:last-child {
  margin-bottom: 0;
}

.content-section h3 {
  font-size: 1.375rem;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.content-section h3::before {
  content: '';
  width: 4px;
  height: 1.5rem;
  background: var(--color-success-500);
  border-radius: var(--radius-full);
}

.content-section p {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-gray-700);
  margin-bottom: var(--space-4);
}

.content-section strong {
  color: var(--color-gray-900);
  font-weight: 600;
}

.content-section code {
  background: var(--color-gray-100);
  color: var(--color-primary-700);
  padding: 0.125rem 0.375rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 500;
}

/* =========================
   Info Boxes
   ========================= */
.info-box {
  display: flex;
  gap: var(--space-4);
  background: rgba(99, 102, 241, 0.05);
  border: 1px solid rgba(99, 102, 241, 0.2);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin: var(--space-6) 0;
}

.info-icon {
  width: 3rem;
  height: 3rem;
  background: var(--color-primary-100);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary-600);
  font-size: 1.25rem;
  flex-shrink: 0;
}

.info-content h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary-800);
  margin-bottom: var(--space-2);
}

.info-content p {
  color: var(--color-primary-700);
  margin-bottom: 0;
}

.warning-box {
  display: flex;
  gap: var(--space-4);
  background: rgba(245, 158, 11, 0.05);
  border: 1px solid rgba(245, 158, 11, 0.3);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin: var(--space-6) 0;
}

.warning-icon {
  width: 3rem;
  height: 3rem;
  background: var(--color-accent-100);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent-600);
  font-size: 1.25rem;
  flex-shrink: 0;
}

.warning-content h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-accent-800);
  margin-bottom: var(--space-2);
}

.warning-content p {
  color: var(--color-accent-700);
  margin-bottom: 0;
}

/* =========================
   Use Cases
   ========================= */
.use-cases {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  margin-top: var(--space-6);
}

@media (min-width: 768px) {
  .use-cases {
    grid-template-columns: repeat(3, 1fr);
  }
}

.use-case {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: all var(--transition-normal);
}

.use-case:hover {
  border-color: var(--color-success-300);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.use-case-icon {
  width: 3.5rem;
  height: 3.5rem;
  background: var(--color-success-50);
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-success-600);
  font-size: 1.5rem;
  margin-bottom: var(--space-3);
}

.use-case-content h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-2);
}

.use-case-content p {
  font-size: 0.875rem;
  color: var(--color-gray-600);
  margin-bottom: 0;
}

/* =========================
   Interactive Examples
   ========================= */
.interactive-example {
  background: var(--color-gray-50);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  margin: var(--space-6) 0;
}

.interactive-example h3 {
  margin-bottom: var(--space-4);
}

.example-box {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
}

.example-input {
  margin-bottom: var(--space-4);
}

.example-input label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-gray-700);
  margin-bottom: var(--space-2);
}

.regex-input {
  display: flex;
  align-items: center;
  background: var(--color-gray-900);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  font-family: var(--font-mono);
  gap: var(--space-2);
}

.regex-input span {
  color: var(--color-accent-400);
  font-weight: 600;
}

.regex-input input {
  background: transparent;
  border: none;
  color: var(--color-primary-300);
  font-family: inherit;
  font-size: 1rem;
  flex: 1;
  outline: none;
}

.example-text {
  margin-bottom: var(--space-4);
}

.example-text label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-gray-700);
  margin-bottom: var(--space-2);
}

.highlighted-text {
  background: var(--color-gray-50);
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
}

.highlighted-text mark {
  background: rgba(16, 185, 129, 0.3);
  color: var(--color-success-800);
  border-radius: 3px;
  padding: 1px 3px;
}

.example-result {
  display: flex;
  justify-content: center;
}

.result-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
}

.result-badge.success {
  background: rgba(16, 185, 129, 0.1);
  color: var(--color-success-700);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

/* =========================
   Pattern Examples
   ========================= */
.pattern-example {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: var(--space-4) 0;
}

.pattern-row {
  display: grid;
  grid-template-columns: 80px 1fr 1fr;
  gap: var(--space-3);
  padding: var(--space-4);
  align-items: center;
  border-bottom: 1px solid var(--color-gray-100);
}

.pattern-row:last-child {
  border-bottom: none;
}

.pattern-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-gray-500);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pattern-code {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  background: var(--color-gray-900);
  color: var(--color-primary-300);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  font-weight: 600;
}

.pattern-text {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--color-gray-700);
}

.pattern-text mark {
  background: rgba(16, 185, 129, 0.3);
  color: var(--color-success-800);
  border-radius: 3px;
  padding: 1px 3px;
}

.pattern-desc {
  font-size: 0.75rem;
  color: var(--color-gray-500);
}

/* =========================
   Comparison Tables
   ========================= */
.comparison-table {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: var(--space-4) 0;
}

.table-header {
  display: grid;
  grid-template-columns: 1fr 1fr 80px;
  gap: var(--space-3);
  padding: var(--space-4);
  background: var(--color-gray-50);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-gray-700);
  border-bottom: 1px solid var(--color-gray-200);
}

.table-row {
  display: grid;
  grid-template-columns: 1fr 1fr 80px;
  gap: var(--space-3);
  padding: var(--space-4);
  align-items: center;
  border-bottom: 1px solid var(--color-gray-100);
  font-size: 0.875rem;
}

.table-row:last-child {
  border-bottom: none;
}

.table-row code {
  font-family: var(--font-mono);
  background: var(--color-gray-100);
  color: var(--color-primary-700);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.match {
  background: rgba(16, 185, 129, 0.3);
  color: var(--color-success-800);
  border-radius: 3px;
  padding: 1px 3px;
  font-family: var(--font-mono);
}

.no-match {
  color: var(--color-gray-500);
  font-family: var(--font-mono);
}

/* =========================
   Practice Boxes
   ========================= */
.practice-box {
  background: var(--color-primary-50);
  border: 2px solid var(--color-primary-200);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  margin: var(--space-6) 0;
}

.practice-box h3 {
  color: var(--color-primary-800);
  margin-bottom: var(--space-4);
}

.practice-box p {
  color: var(--color-primary-700);
}

.practice-input {
  margin-bottom: var(--space-4);
}

.practice-input label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-primary-800);
  margin-bottom: var(--space-2);
}

.practice-field {
  width: 100%;
  padding: var(--space-3);
  border: 2px solid var(--color-primary-300);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: var(--font-mono);
  background: white;
  transition: all var(--transition-normal);
}

.practice-field:focus {
  outline: none;
  border-color: var(--color-primary-500);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.practice-text {
  background: white;
  border: 1px solid var(--color-primary-300);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--color-gray-800);
  margin-bottom: var(--space-4);
}

.practice-result {
  background: white;
  border: 1px solid var(--color-primary-300);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  min-height: 60px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.no-result {
  color: var(--color-gray-500);
  text-align: center;
  padding: var(--space-4);
  font-style: italic;
}

/* =========================
   Coming Soon
   ========================= */
.coming-soon {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-12) var(--space-4);
  color: var(--color-gray-500);
}

.coming-soon i {
  font-size: 3rem;
  margin-bottom: var(--space-4);
  color: var(--color-gray-400);
}

.coming-soon h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-gray-700);
  margin-bottom: var(--space-2);
}

.coming-soon p {
  margin-bottom: 0;
}

/* =========================
   Completion Celebration
   ========================= */
.completion-celebration {
  text-align: center;
  padding: var(--space-8);
}

.celebration-icon {
  width: 5rem;
  height: 5rem;
  background: linear-gradient(135deg, var(--color-success-500), var(--color-accent-500));
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 2.5rem;
  margin: 0 auto var(--space-6);
  animation: bounce 1s infinite;
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(-10px); }
  60% { transform: translateY(-5px); }
}

.completion-celebration h3 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-gray-900);
  margin-bottom: var(--space-4);
}

.next-steps {
  margin-top: var(--space-8);
}

.next-steps h4 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-gray-800);
  margin-bottom: var(--space-6);
}

.step-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  margin-top: var(--space-6);
}

@media (min-width: 768px) {
  .step-cards {
    grid-template-columns: repeat(3, 1fr);
  }
}

.step-card {
  background: white;
  border: 2px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  text-align: center;
  text-decoration: none;
  color: var(--color-gray-700);
  transition: all var(--transition-normal);
}

.step-card:hover {
  border-color: var(--color-primary-400);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.step-card i {
  font-size: 2rem;
  color: var(--color-primary-600);
  margin-bottom: var(--space-3);
}

.step-card h5 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-2);
}

.step-card p {
  font-size: 0.875rem;
  margin-bottom: 0;
}

/* =========================
   Lesson Navigation
   ========================= */
.lesson-navigation {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-gray-200);
  gap: var(--space-4);
}

@media (max-width: 640px) {
  .lesson-navigation {
    flex-direction: column;
    align-items: stretch;
  }
  
  .lesson-navigation .btn {
    width: 100%;
    justify-content: center;
  }
}

.prev-lesson,
.next-lesson {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.prev-lesson i {
  order: -1;
}

.next-lesson i {
  order: 1;
}

/* =========================
   Quick Navigation
   ========================= */
.quick-nav {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  background: white;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-full);
  padding: var(--space-3);
  box-shadow: var(--shadow-lg);
  z-index: var(--z-popover);
}

.quick-nav-btn {
  width: 2.5rem;
  height: 2.5rem;
  background: var(--color-gray-100);
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-full);
  color: var(--color-gray-600);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
}

.quick-nav-btn:hover:not(:disabled) {
  background: var(--color-primary-50);
  border-color: var(--color-primary-300);
  color: var(--color-primary-600);
}

.quick-nav-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.lesson-indicator {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-gray-700);
  padding: 0 var(--space-2);
}

/* =========================
   Responsive Design
   ========================= */
@media (max-width: 767px) {
  .guide-header {
    padding: 6rem 0 3rem;
  }
  
  .header-title {
    font-size: 2rem;
  }
  
  .toc-grid {
    grid-template-columns: 1fr;
  }
  
  .lesson {
    padding: var(--space-6);
  }
  
  .lesson-title {
    font-size: 1.5rem;
  }
  
  .comparison-table .table-header,
  .comparison-table .table-row {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }
  
  .pattern-row {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }
  
  .quick-nav {
    bottom: var(--space-4);
    right: var(--space-4);
  }
}

@media (max-width: 480px) {
  .use-cases {
    grid-template-columns: 1fr;
  }
  
  .regex-input {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-2);
  }
  
  .regex-input input {
    text-align: center;
  }
  
  .quick-nav {
    flex-direction: column;
    gap: var(--space-1);
  }
}

/* =========================
   Animation Performance
   ========================= */
.lesson,
.toc-item,
.use-case,
.step-card {
  will-change: transform;
}

@media (prefers-reduced-motion: reduce) {
  .lesson,
  .toc-item,
  .use-case,
  .step-card,
  .celebration-icon {
    animation: none !important;
    transition: none !important;
  }
  
  .progress-fill::after {
    display: none;
  }
}

/* =========================
   Interactive Demo Enhancements (추가)
   ========================= */
.interactive-demo {
  background: var(--color-gray-50);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-top: var(--space-6);
}

.interactive-demo h3 {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  color: var(--color-gray-900);
  font-weight: 600;
}

.interactive-demo h3 i {
  color: var(--color-primary-600);
}

.demo-container {
  background: white;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.demo-content {
  padding: var(--space-5);
}

.demo-input {
  margin-bottom: var(--space-4);
}

.demo-input label {
  display: block;
  font-weight: 600;
  color: var(--color-gray-700);
  margin-bottom: var(--space-2);
  font-size: 0.875rem;
}

.practice-field {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 2px solid var(--color-gray-300);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  background: var(--color-gray-50);
  transition: all 0.2s ease;
}

.practice-field:focus {
  outline: none;
  border-color: var(--color-primary-500);
  background: white;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.demo-test {
  margin-bottom: var(--space-4);
}

.demo-test label {
  display: block;
  font-weight: 600;
  color: var(--color-gray-700);
  margin-bottom: var(--space-2);
  font-size: 0.875rem;
}

.test-text {
  background: var(--color-gray-900);
  color: var(--color-gray-100);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  min-height: 60px;
  border: 1px solid var(--color-gray-700);
}

.test-text mark {
  background-color: #10b981 !important;
  color: white !important;
  padding: 2px 4px;
  border-radius: 3px;
  font-weight: 600;
}

.demo-result {
  min-height: 50px;
  display: flex;
  align-items: center;
}

.demo-success {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-success-700);
  font-weight: 600;
  background: var(--color-success-50);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-success-200);
  animation: fadeInUp 0.3s ease;
}

.demo-info {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-primary-700);
  font-weight: 500;
  background: var(--color-primary-50);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-primary-200);
  animation: fadeInUp 0.3s ease;
}

.demo-error {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-error-700);
  font-weight: 500;
  background: var(--color-error-50);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-error-200);
  animation: fadeInUp 0.3s ease;
}

.demo-explanation {
  color: var(--color-gray-600);
  font-size: 0.875rem;
  padding: var(--space-3) var(--space-4);
  background: var(--color-gray-50);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-gray-200);
}

/* =========================
   TOC Completed Enhancement (기존 수정)
   ========================= */
.toc-item.completed {
  background: linear-gradient(135deg, var(--color-success-50), var(--color-success-25));
  border-color: var(--color-success-400);
  border-width: 2px;
}

.toc-item.completed .toc-content h4 {
  color: var(--color-success-700);
}

/* TOC 카드 자체 테두리 변경 */
.toc-card.has-completed {
  border-color: var(--color-success-400);
  border-width: 2px;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.15);
}

/* =========================
   Progress Fill Enhancement (기존 수정)
   ========================= */
.progress-fill {
  transition: width 0.5s ease;
}

/* =========================
   Next Button Auto-enable (추가)
   ========================= */
.next-lesson:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  background: var(--color-gray-400);
}

.next-lesson.auto-enabled {
  animation: buttonActivate 0.5s ease;
}

@keyframes buttonActivate {
  0% {
    opacity: 0.5;
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

/* =========================
   Animation Enhancements (추가)
   ========================= */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes completionPulse {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.02);
    box-shadow: 0 4px 20px rgba(16, 185, 129, 0.3);
  }
  100% {
    transform: scale(1);
  }
}

/* =========================
   Responsive Enhancements (추가)
   ========================= */
@media (max-width: 768px) {
  .interactive-demo {
    padding: var(--space-4);
    margin-top: var(--space-4);
  }
  
  .demo-content {
    padding: var(--space-4);
  }
  
  .practice-field {
    font-size: 0.8rem;
  }
  
  .test-text {
    font-size: 0.8rem;
    padding: var(--space-3);
  }
}

/* 버튼 활성화 애니메이션 */
@keyframes buttonActivate {
    0% {
        transform: scale(1);
        box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 8px 16px rgba(59, 130, 246, 0.3);
    }
    100% {
        transform: scale(1);
        box-shadow: 0 4px 8px rgba(59, 130, 246, 0.2);
    }
}

.next-lesson.activated {
    animation: buttonActivate 0.5s ease-out;
}

/* TOC 아이템 상태별 스타일 */
/* 기본 상태 */
.toc-item {
    border: 1px solid #d1d5db;
}

/* 완료된 레슨 - 초록 테두리 + 체크 표시 */
.toc-item.completed {
    border-color: #10b981 !important;
    background: rgba(16, 185, 129, 0.05);
}

.toc-item.completed .toc-number {
    background: #10b981;
    color: white;
}

.toc-item.completed .toc-check {
    display: block;
    color: #10b981;
}

/* 현재 레슨 - 검정 테두리 (완료 여부 관계없이) */
.toc-item.current {
    border-color: #374151 !important;
    background: rgba(55, 65, 81, 0.05);
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.toc-item.current .toc-number {
    background: #374151;
    color: white;
}

/* 현재 레슨이면서 완료된 레슨 - 검정 테두리 + 체크 표시 */
.toc-item.current.completed .toc-check {
    display: block;
    color: #374151;
}

/* 체크 표시 기본 숨김 */
.toc-check {
    display: none;
}

/* 연습 결과 스타일 - 흰색 배경 */
.demo-explanation.success {
    background: white;
    color: #065f46;
    border: 1px solid #10b981;
    border-left: 4px solid #10b981;
}

.demo-explanation.warning {
    background: white;
    color: #92400e;
    border: 1px solid #f59e0b;
    border-left: 4px solid #f59e0b;
}

.demo-explanation.error {
    background: white;
    color: #991b1b;
    border: 1px solid #ef4444;
    border-left: 4px solid #ef4444;
}

.demo-explanation {
    background: white;
    color: #374151;
    border: 1px solid #d1d5db;
    border-left: 4px solid #6b7280;
    padding: 12px 16px;
    border-radius: 6px;
    margin-top: 12px;
}

/* 레슨 완료 메시지 애니메이션 */
@keyframes completionPulse {
    0% {
        opacity: 0;
        transform: translateY(-10px);
    }
    50% {
        opacity: 1;
        transform: translateY(0);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

.demo-explanation.success span {
    animation: completionPulse 0.6s ease-out;
}