/* ===============================================
   RHCSA Study Guide - DevOps ni Diary
   Modern, Professional, Mobile-Responsive Styles
   =============================================== */

/* CSS Variables for Theme Management */
:root {
  /* Light Theme Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #adb5bd;

  /* Brand Colors */
  --color-brand: #ee0000;
  --color-brand-dark: #cc0000;
  --color-accent: #0066cc;
  --color-accent-dark: #0052a3;

  /* Semantic Colors */
  --color-success: #28a745;
  --color-warning: #ffc107;
  --color-danger: #dc3545;
  --color-info: #17a2b8;

  /* UI Elements */
  --border-color: #dee2e6;
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Code Block Colors */
  --code-bg: #f4f4f4;
  --code-border: #e1e1e1;
  --code-text: #333333;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #1a1a1a;
  --bg-secondary: #2d2d2d;
  --bg-tertiary: #3a3a3a;
  --text-primary: #e9ecef;
  --text-secondary: #adb5bd;
  --text-muted: #6c757d;
  --border-color: #404040;
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
  --code-bg: #2d2d2d;
  --code-border: #404040;
  --code-text: #e9ecef;
}

/* ===============================================
   RESET & BASE STYLES
   =============================================== */

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu",
    "Cantarell", "Helvetica Neue", sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition:
    background-color var(--transition-normal),
    color var(--transition-normal);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ===============================================
   NAVIGATION BAR
   =============================================== */

.navbar {
  position: sticky;
  top: 0;
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  z-index: 1000;
  transition: all var(--transition-normal);
}

.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-brand);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.logo:hover {
  transform: scale(1.05);
}

.logo-icon {
  font-size: 1.5rem;
  display: inline-block;
  animation: float 3s ease-in-out infinite;
}

.nav-search {
  position: relative;
  flex: 1;
  max-width: 400px;
}

#searchInput {
  width: 100%;
  padding: 0.6rem 2.5rem 0.6rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.95rem;
  transition: all var(--transition-fast);
}

#searchInput:focus {
  outline: none;
  border-color: var(--color-brand);
  box-shadow: 0 0 0 3px rgba(238, 0, 0, 0.1);
}

.search-icon {
  position: absolute;
  right: 0.8rem;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-brand);
  background-color: var(--bg-secondary);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 1.2rem;
  transition: all var(--transition-fast);
  background-color: var(--bg-secondary);
}

.theme-toggle:hover {
  transform: scale(1.1);
  border-color: var(--color-brand);
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.mobile-menu-toggle span {
  display: block;
  width: 25px;
  height: 3px;
  background-color: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

/* ===============================================
   HERO SECTION
   =============================================== */

.hero {
  padding: 5rem 2rem;
  background: linear-gradient(-45deg, #1a1a2e, #16213e, #0f3460, #533483);
  background-size: 400% 400%;
  animation: gradientShift 15s ease infinite;
  border-bottom: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}

[data-theme="light"] .hero {
  background: linear-gradient(-45deg, #f8f9fa, #e9ecef, #dee2e6, #f5f5f5);
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at 20% 80%, rgba(238, 0, 0, 0.15) 0%, transparent 50%),
              radial-gradient(circle at 80% 20%, rgba(0, 102, 204, 0.15) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: 1rem;
  color: #ffffff;
  line-height: 1.2;
  animation: fadeInUp 0.8s ease-out;
  text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.3);
}

[data-theme="light"] .hero-title {
  color: var(--text-primary);
  text-shadow: none;
}

.hero-subtitle {
  font-size: 1.6rem;
  color: #ff6b6b;
  margin-bottom: 1rem;
  font-weight: 600;
  animation: fadeInUp 0.8s ease-out 0.1s backwards;
}

[data-theme="light"] .hero-subtitle {
  color: var(--color-brand);
}

.hero-description {
  font-size: 1.15rem;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 2.5rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

[data-theme="light"] .hero-description {
  color: var(--text-secondary);
}

.hero-buttons {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 3rem;
  animation: fadeInUp 0.8s ease-out 0.3s backwards;
}

.btn {
  padding: 1rem 2.5rem;
  border-radius: var(--radius-lg);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  display: inline-block;
  border: none;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-brand) 0%, #ff6b6b 100%);
  color: white;
  box-shadow: 0 4px 15px rgba(238, 0, 0, 0.3);
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transition: left 0.5s ease;
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--color-brand-dark) 0%, var(--color-brand) 100%);
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 8px 25px rgba(238, 0, 0, 0.4);
}

.btn-secondary {
  background-color: rgba(255, 255, 255, 0.1);
  color: #ffffff;
  border: 2px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
}

[data-theme="light"] .btn-secondary {
  background-color: transparent;
  color: var(--text-primary);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.2);
  border-color: var(--color-brand);
  color: #ffffff;
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

[data-theme="light"] .btn-secondary:hover {
  background-color: var(--bg-secondary);
  color: var(--color-brand);
}

.hero-image {
  max-width: 600px;
  margin: 0 auto;
  animation: fadeInUp 0.8s ease-out 0.4s backwards;
}

.terminal-window {
  background: linear-gradient(145deg, #1a1a2e 0%, #0a0a15 100%);
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4), 0 0 40px rgba(238, 0, 0, 0.1);
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.1);
  animation: pulseGlow 4s ease-in-out infinite;
  transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.terminal-window:hover {
  transform: translateY(-10px) scale(1.02);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5), 0 0 60px rgba(238, 0, 0, 0.2);
}

.terminal-header {
  background: linear-gradient(135deg, #2d2d44 0%, #1a1a2e 100%);
  padding: 0.75rem 1rem;
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.terminal-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.terminal-dot:hover {
  transform: scale(1.3);
}

.terminal-dot.red {
  background-color: #ff5f56;
  box-shadow: 0 0 8px #ff5f56;
}

.terminal-dot.yellow {
  background-color: #ffbd2e;
  box-shadow: 0 0 8px #ffbd2e;
}

.terminal-dot.green {
  background-color: #27c93f;
  box-shadow: 0 0 8px #27c93f;
}

.terminal-body {
  padding: 1.5rem;
  font-family: "Courier New", Courier, monospace;
  font-size: 0.9rem;
  line-height: 1.8;
  background: linear-gradient(180deg, #1a1a2e 0%, #0a0a15 100%);
}

.terminal-body p {
  margin: 0.25rem 0;
  opacity: 0;
  animation: fadeInLeft 0.5s ease-out forwards;
}

.terminal-body p:nth-child(1) { animation-delay: 0.6s; }
.terminal-body p:nth-child(2) { animation-delay: 0.9s; }
.terminal-body p:nth-child(3) { animation-delay: 1.2s; }
.terminal-body p:nth-child(4) { animation-delay: 1.5s; }

.prompt {
  color: #ff6b6b;
  font-weight: bold;
  text-shadow: 0 0 10px rgba(255, 107, 107, 0.5);
}

.terminal-output {
  color: #a0a0b0;
}

.text-success {
  color: #27c93f;
  font-weight: bold;
  text-shadow: 0 0 10px rgba(39, 201, 63, 0.5);
}

/* ===============================================
   SECTIONS
   =============================================== */

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.section-description {
  text-align: center;
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 3rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

/* About Section */
.about-section {
  padding: 4rem 2rem;
  background-color: var(--bg-primary);
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.about-card {
  background-color: var(--bg-secondary);
  padding: 2rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  position: relative;
  overflow: hidden;
}

.about-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, transparent 0%, rgba(238, 0, 0, 0.03) 100%);
  opacity: 0;
  transition: opacity 0.3s ease;
}

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

.about-card:hover {
  transform: translateY(-10px) scale(1.02);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
  border-color: var(--color-brand);
}

.about-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  display: inline-block;
  animation: float 4s ease-in-out infinite;
}

.about-card:nth-child(1) .about-icon { animation-delay: 0s; }
.about-card:nth-child(2) .about-icon { animation-delay: 0.5s; }
.about-card:nth-child(3) .about-icon { animation-delay: 1s; }
.about-card:nth-child(4) .about-icon { animation-delay: 1.5s; }

.about-card h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
  transition: color 0.3s ease;
}

.about-card:hover h3 {
  color: var(--color-brand);
}

.about-card p {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Chapters Section */
.chapters-section {
  padding: 4rem 2rem;
  background-color: var(--bg-secondary);
}

.chapters-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
}

.chapter-card {
  background-color: var(--bg-primary);
  padding: 2rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  text-decoration: none;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.chapter-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(238, 0, 0, 0.05), transparent);
  transition: left 0.6s ease;
}

.chapter-card:hover::before {
  left: 100%;
}

.chapter-card:hover {
  transform: translateY(-12px) scale(1.02);
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.15), 0 0 0 1px var(--color-brand);
  border-color: var(--color-brand);
}

.chapter-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--color-brand);
  opacity: 0.3;
  margin-bottom: 1rem;
  transition: all 0.3s ease;
}

.chapter-card:hover .chapter-number {
  opacity: 0.6;
  transform: scale(1.1);
}

.chapter-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  transition: color 0.3s ease;
}

.chapter-card:hover .chapter-title {
  color: var(--color-brand);
}

.chapter-description {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.chapter-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.topic-tag {
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

.chapter-card:hover .topic-tag {
  background-color: rgba(238, 0, 0, 0.1);
  border-color: rgba(238, 0, 0, 0.3);
  color: var(--color-brand);
}

/* Features Section */
.features-section {
  padding: 4rem 2rem;
  background-color: var(--bg-primary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.feature-item {
  text-align: center;
  padding: 1.5rem;
}

.feature-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.feature-item h3 {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.feature-item p {
  color: var(--text-secondary);
}

/* ===============================================
   CHAPTER PAGE STYLES
   =============================================== */

.chapter-page {
  display: flex;
  min-height: calc(100vh - 80px);
}

.sidebar {
  width: 280px;
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: 2rem 1rem;
  position: sticky;
  top: 80px;
  height: calc(100vh - 80px);
  overflow-y: auto;
}

.sidebar-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
  padding: 0 0.5rem;
}

.sidebar-nav {
  list-style: none;
}

.sidebar-nav li {
  margin-bottom: 0.5rem;
}

.sidebar-nav a {
  display: block;
  padding: 0.5rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  font-size: 0.9rem;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
  background-color: var(--bg-tertiary);
  color: var(--color-brand);
  padding-left: 1rem;
}

.main-content {
  flex: 1;
  padding: 2rem;
  max-width: 900px;
  margin: 0 auto;
}

.chapter-header {
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--border-color);
}

.chapter-meta {
  display: flex;
  gap: 1rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.meta-badge {
  padding: 0.5rem 1rem;
  background-color: var(--bg-secondary);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.chapter-header h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.chapter-intro {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

/* Table of Contents */
.table-of-contents {
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  margin-bottom: 2rem;
}

.table-of-contents h2 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.toc-list {
  list-style: none;
}

.toc-list li {
  margin-bottom: 0.5rem;
}

.toc-list a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.toc-list a:hover {
  color: var(--color-brand);
}

/* Content Sections */
.content-section {
  margin-bottom: 3rem;
}

.content-section h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
  padding-top: 1rem;
}

.content-section h3 {
  font-size: 1.5rem;
  margin: 1.5rem 0 1rem 0;
  color: var(--text-primary);
}

.content-section h4 {
  font-size: 1.2rem;
  margin: 1rem 0 0.5rem 0;
  color: var(--text-primary);
}

.content-section p {
  margin-bottom: 1rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

.content-section ul,
.content-section ol {
  margin-bottom: 1rem;
  padding-left: 2rem;
  color: var(--text-secondary);
}

.content-section li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}

/* Code Blocks */
pre {
  background-color: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  overflow-x: auto;
  margin-bottom: 1.5rem;
  position: relative;
}

code {
  font-family: "Courier New", Courier, monospace;
  font-size: 0.9rem;
  color: var(--code-text);
  line-height: 1.6;
}

pre code {
  display: block;
}

p code,
li code {
  background-color: var(--code-bg);
  padding: 0.2rem 0.4rem;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
  border: 1px solid var(--code-border);
}

/* Info Boxes */
.info-box {
  padding: 1.5rem;
  border-radius: var(--radius-md);
  margin-bottom: 1.5rem;
  border-left: 4px solid;
}

.note {
  background-color: rgba(23, 162, 184, 0.1);
  border-color: var(--color-info);
}

.warning {
  background-color: rgba(255, 193, 7, 0.1);
  border-color: var(--color-warning);
}

.tip {
  background-color: rgba(40, 167, 69, 0.1);
  border-color: var(--color-success);
}

.danger {
  background-color: rgba(220, 53, 69, 0.1);
  border-color: var(--color-danger);
}

.info-box-title {
  font-weight: 700;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.note .info-box-title {
  color: var(--color-info);
}

.warning .info-box-title {
  color: var(--color-warning);
}

.tip .info-box-title {
  color: var(--color-success);
}

.danger .info-box-title {
  color: var(--color-danger);
}

/* Procedures */
.procedure {
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
}

.procedure h4 {
  margin-top: 0;
}

.procedure ol {
  counter-reset: step-counter;
  list-style: none;
  padding-left: 0;
}

.procedure ol li {
  counter-increment: step-counter;
  padding-left: 3rem;
  position: relative;
  margin-bottom: 1rem;
}

.procedure ol li::before {
  content: counter(step-counter);
  position: absolute;
  left: 0;
  top: 0;
  background-color: var(--color-brand);
  color: white;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
}

/* Quiz Section */
.quiz-section {
  background-color: var(--bg-secondary);
  padding: 2rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  margin: 2rem 0;
}

.quiz-section h3 {
  margin-top: 0;
  color: var(--color-brand);
}

.quiz-question {
  margin-bottom: 2rem;
  padding: 1.5rem;
  background-color: var(--bg-primary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.quiz-question h4 {
  margin-top: 0;
  margin-bottom: 1rem;
}

.quiz-options {
  list-style: none;
  padding-left: 0;
}

.quiz-options li {
  padding: 0.75rem;
  margin-bottom: 0.5rem;
  background-color: var(--bg-secondary);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid var(--border-color);
}

.quiz-options li:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--color-brand);
}

.quiz-answer {
  margin-top: 1rem;
  padding: 1rem;
  background-color: rgba(40, 167, 69, 0.1);
  border-radius: var(--radius-sm);
  border-left: 4px solid var(--color-success);
  display: none;
}

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

/* Navigation Buttons */
.chapter-navigation {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border-color);
}

.nav-button {
  padding: 1rem 1.5rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--text-primary);
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-button:hover {
  background-color: var(--color-brand);
  color: white;
  border-color: var(--color-brand);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.nav-button.prev::before {
  content: "←";
}

.nav-button.next::after {
  content: "→";
}

/* ===============================================
   FOOTER
   =============================================== */

.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 3rem 2rem 1rem 2rem;
  margin-top: 4rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-section p,
.footer-text {
  color: var(--text-secondary);
  line-height: 1.6;
}

.social-links {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
}

.social-link {
  color: var(--text-primary);
  text-decoration: none;
  padding: 0.5rem 1rem;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  border: 1px solid var(--border-color);
}

.social-link:hover {
  background-color: var(--color-brand);
  color: white;
  border-color: var(--color-brand);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-muted);
}

/* ===============================================
   RESPONSIVE DESIGN
   =============================================== */

@media (max-width: 968px) {
  .chapter-page {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    position: static;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }

  .main-content {
    padding: 1.5rem;
  }
}

@media (max-width: 768px) {
  .nav-container {
    padding: 1rem;
    flex-wrap: wrap;
  }

  .nav-search {
    order: 3;
    width: 100%;
    max-width: 100%;
    margin-top: 1rem;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem;
    flex-direction: column;
    box-shadow: var(--shadow-md);
  }

  .nav-links.active {
    display: flex;
  }

  .mobile-menu-toggle {
    display: flex;
  }

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

  .hero-subtitle {
    font-size: 1.2rem;
  }

  .section-title {
    font-size: 2rem;
  }

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

  .chapter-navigation {
    flex-direction: column;
  }

  .nav-button {
    width: 100%;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 2rem 1rem;
  }

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

  .about-grid,
  .features-grid {
    grid-template-columns: 1fr;
  }

  .procedure ol li {
    padding-left: 2.5rem;
  }

  .procedure ol li::before {
    width: 1.5rem;
    height: 1.5rem;
    font-size: 0.85rem;
  }
}

/* ===============================================
   UTILITY CLASSES
   =============================================== */

.hidden {
  display: none !important;
}

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

.text-right {
  text-align: right;
}

.mt-1 {
  margin-top: 0.5rem;
}
.mt-2 {
  margin-top: 1rem;
}
.mt-3 {
  margin-top: 1.5rem;
}
.mt-4 {
  margin-top: 2rem;
}

.mb-1 {
  margin-bottom: 0.5rem;
}
.mb-2 {
  margin-bottom: 1rem;
}
.mb-3 {
  margin-bottom: 1.5rem;
}
.mb-4 {
  margin-bottom: 2rem;
}

/* ===============================================
   ADVANCED ANIMATIONS & EFFECTS
   =============================================== */

/* Keyframe Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(50px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInLeft {
  from {
    opacity: 0;
    transform: translateX(-50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes fadeInRight {
  from {
    opacity: 0;
    transform: translateX(50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float {
  0%,
  100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-15px);
  }
}

@keyframes pulse {
  0%,
  100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.05);
    opacity: 0.9;
  }
}

@keyframes pulseGlow {
  0%,
  100% {
    box-shadow:
      0 0 5px rgba(238, 0, 0, 0.3),
      0 0 10px rgba(238, 0, 0, 0.2);
  }
  50% {
    box-shadow:
      0 0 20px rgba(238, 0, 0, 0.5),
      0 0 30px rgba(238, 0, 0, 0.3);
  }
}

@keyframes gradientShift {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}

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

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

@keyframes rotate {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

@keyframes wiggle {
  0%,
  100% {
    transform: rotate(0deg);
  }
  25% {
    transform: rotate(5deg);
  }
  75% {
    transform: rotate(-5deg);
  }
}

@keyframes typewriter {
  from {
    width: 0;
  }
  to {
    width: 100%;
  }
}

@keyframes blink {
  0%,
  50% {
    opacity: 1;
  }
  51%,
  100% {
    opacity: 0;
  }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes ripple {
  0% {
    transform: scale(0);
    opacity: 1;
  }
  100% {
    transform: scale(4);
    opacity: 0;
  }
}

@keyframes borderGlow {
  0%,
  100% {
    border-color: var(--color-brand);
    box-shadow: 0 0 5px var(--color-brand);
  }
  50% {
    border-color: var(--color-accent);
    box-shadow: 0 0 15px var(--color-accent);
  }
}

/* Animation Utility Classes */
.fade-in {
  animation: fadeIn 0.6s ease-out forwards;
}

.fade-in-up {
  animation: fadeInUp 0.7s ease-out forwards;
}

.fade-in-left {
  animation: fadeInLeft 0.7s ease-out forwards;
}

.fade-in-right {
  animation: fadeInRight 0.7s ease-out forwards;
}

.slide-down {
  animation: slideDown 0.5s ease-out forwards;
}

.float-animation {
  animation: float 3s ease-in-out infinite;
}

.pulse-animation {
  animation: pulse 2s ease-in-out infinite;
}

.bounce-animation {
  animation: bounce 2s ease infinite;
}

.wiggle-animation {
  animation: wiggle 0.5s ease-in-out infinite;
}

.scale-in {
  animation: scaleIn 0.5s ease-out forwards;
}

/* Staggered Animation Delays */
.stagger-1 {
  animation-delay: 0.1s;
}
.stagger-2 {
  animation-delay: 0.2s;
}
.stagger-3 {
  animation-delay: 0.3s;
}
.stagger-4 {
  animation-delay: 0.4s;
}
.stagger-5 {
  animation-delay: 0.5s;
}
.stagger-6 {
  animation-delay: 0.6s;
}
.stagger-7 {
  animation-delay: 0.7s;
}
.stagger-8 {
  animation-delay: 0.8s;
}

/* Pre-animation state for reveal */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition:
    opacity 0.6s ease-out,
    transform 0.6s ease-out;
}

.animate-on-scroll.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* Smooth Scrollbar */
::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 6px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}