/* CSS Variables */
:root {
  /* Colors */
  --primary-color: #0078d7;
  --secondary-color: #ff8c00;
  --text-color: #333;
  --light-text-color: #666;
  --background-color: #fff;
  --dark-background-color: #1e1e1e;
  --code-background: #f5f5f5;
  --border-color: #ddd;
  --success-color: #28a745;
  --error-color: #dc3545;
  --warning-color: #ffc107;
  --info-color: #17a2b8;
  
  /* Typography */
  --base-font-size: 16px;
  --heading-font-family: 'Roboto', sans-serif;
  --body-font-family: 'Open Sans', sans-serif;
  --code-font-family: 'Source Code Pro', monospace;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* Layout */
  --container-width: 1140px;
  --border-radius: 4px;
  --box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-speed: 0.3s;
}

/* Dark Mode Variables */
.dark-mode {
  --text-color: #e6e6e6;
  --light-text-color: #b0b0b0;
  --background-color: #1e1e1e;
  --dark-background-color: #121212;
  --code-background: #2d2d2d;
  --border-color: #444;
}

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

html {
  font-size: var(--base-font-size);
  scroll-behavior: smooth;
}

body {
  font-family: var(--body-font-family);
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--background-color);
  transition: background-color var(--transition-speed), color var(--transition-speed);
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--heading-font-family);
  margin-bottom: var(--spacing-md);
  line-height: 1.3;
  color: var(--text-color);
}

h1 {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-lg);
}

h2 {
  font-size: 2rem;
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
}

h3 {
  font-size: 1.5rem;
  margin-top: var(--spacing-lg);
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--spacing-md);
}

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

a:hover {
  text-decoration: underline;
}

ul, ol {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-lg);
}

code {
  font-family: var(--code-font-family);
  background-color: var(--code-background);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  font-size: 0.95em;
}

pre {
  font-family: var(--code-font-family);
  background-color: var(--code-background);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
  border: 1px solid var(--border-color);
}

pre code {
  padding: 0;
  background-color: transparent;
}

blockquote {
  border-left: 4px solid var(--secondary-color);
  padding-left: var(--spacing-md);
  margin-bottom: var(--spacing-md);
  font-style: italic;
  color: var(--light-text-color);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: var(--spacing-md) 0;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--spacing-md);
}

table th, table td {
  padding: var(--spacing-sm);
  border: 1px solid var(--border-color);
  text-align: left;
}

table th {
  background-color: var(--code-background);
}

/* Header */
.header {
  padding: var(--spacing-md) 0;
  background-color: var(--background-color);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--box-shadow);
  transition: background-color var(--transition-speed);
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  display: flex;
  align-items: center;
}

.logo a {
  color: var(--text-color);
  text-decoration: none;
}

.logo img {
  height: 40px;
  margin-right: var(--spacing-sm);
  margin: 0;
}

.nav {
  display: flex;
}

.nav-list {
  display: flex;
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-item {
  margin-left: var(--spacing-md);
}

.nav-link {
  color: var(--text-color);
  text-decoration: none;
  font-weight: 500;
  padding: var(--spacing-sm);
  border-radius: var(--border-radius);
  transition: background-color var(--transition-speed);
}

.nav-link:hover {
  background-color: rgba(0, 0, 0, 0.05);
  text-decoration: none;
}

.dark-mode .nav-link:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

.nav-link.active {
  color: var(--primary-color);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-color);
  transition: color var(--transition-speed);
}

/* Hero Section */
.hero {
  padding: var(--spacing-xl) 0;
  background: linear-gradient(135deg, var(--primary-color), #1e88e5);
  color: white;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
  color: white;
}

.hero p {
  font-size: 1.25rem;
  max-width: 800px;
  margin: 0 auto var(--spacing-lg);
}

.hero-buttons {
  display: flex;
  justify-content: center;
  gap: var(--spacing-md);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  font-weight: 600;
  text-decoration: none;
  transition: background-color var(--transition-speed), transform var(--transition-speed);
}

.btn:hover {
  background-color: #0062b1;
  transform: translateY(-2px);
  text-decoration: none;
}

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

.btn-secondary:hover {
  background-color: #e07800;
}

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

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

/* Feature Cards */
.feature-section {
  padding: var(--spacing-xl) 0;
}

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-md);
}

.card {
  background-color: var(--background-color);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--box-shadow);
  transition: transform var(--transition-speed);
}

.card:hover {
  transform: translateY(-5px);
}

.card-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.card-content {
  padding: var(--spacing-md);
}

.card-title {
  margin-top: 0;
  margin-bottom: var(--spacing-sm);
}

.card-text {
  color: var(--light-text-color);
}

/* Newsletter Form */
.newsletter {
  background-color: var(--code-background);
  padding: var(--spacing-xl) 0;
  text-align: center;
}

.newsletter h2 {
  margin-top: 0;
}

.form-group {
  max-width: 600px;
  margin: 0 auto;
}

.input-group {
  display: flex;
  margin-bottom: var(--spacing-md);
}

.form-control {
  flex: 1;
  padding: var(--spacing-sm);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius) 0 0 var(--border-radius);
  font-size: 1rem;
  font-family: var(--body-font-family);
}

.form-control:focus {
  outline: none;
  border-color: var(--primary-color);
}

.input-group .btn {
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
}

/* Content Sections */
.content-section {
  padding: var(--spacing-xl) 0;
}

.content-container {
  display: grid;
  grid-template-columns: 3fr 1fr;
  gap: var(--spacing-lg);
}

.sidebar {
  position: sticky;
  top: 80px;
  height: max-content;
}

.toc {
  background-color: var(--code-background);
  border-radius: var(--border-radius);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.toc-title {
  margin-top: 0;
}

.toc-list {
  list-style: none;
  padding: 0;
}

.toc-item {
  margin-bottom: var(--spacing-sm);
}

.toc-link {
  display: block;
  padding: var(--spacing-xs) 0;
  color: var(--text-color);
  text-decoration: none;
  border-left: 2px solid transparent;
  padding-left: var(--spacing-sm);
  transition: border-color var(--transition-speed);
}

.toc-link:hover, .toc-link.active {
  border-left-color: var(--primary-color);
  color: var(--primary-color);
}

.toc-link.level-2 {
  padding-left: var(--spacing-md);
}

.toc-link.level-3 {
  padding-left: var(--spacing-lg);
}

/* Code Editor */
.code-editor {
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  margin-bottom: var(--spacing-lg);
  overflow: hidden;
}

.code-editor-header {
  background-color: var(--code-background);
  padding: var(--spacing-sm) var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.editor-tabs {
  display: flex;
}

.editor-tab {
  padding: var(--spacing-xs) var(--spacing-sm);
  margin-right: var(--spacing-xs);
  border-radius: var(--border-radius);
  cursor: pointer;
  background-color: transparent;
  border: none;
  font-family: var(--body-font-family);
  transition: background-color var(--transition-speed);
}

.editor-tab.active {
  background-color: var(--primary-color);
  color: white;
}

.editor-actions {
  display: flex;
}

.editor-action {
  padding: var(--spacing-xs) var(--spacing-sm);
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-color);
  transition: color var(--transition-speed);
  font-size: 0.9rem;
}

.editor-action:hover {
  color: var(--primary-color);
}

.code-editor-content {
  padding: var(--spacing-md);
  background-color: var(--code-background);
}

.code-editor-textarea {
  width: 100%;
  min-height: 200px;
  font-family: var(--code-font-family);
  font-size: 0.9rem;
  border: none;
  background-color: var(--code-background);
  color: var(--text-color);
  resize: vertical;
}

.code-editor-textarea:focus {
  outline: none;
}

.code-preview {
  padding: var(--spacing-md);
  border-top: 1px solid var(--border-color);
  background-color: white;
}

/* Progress Tracker */
.progress-tracker {
  margin-bottom: var(--spacing-lg);
}

.progress-bar {
  height: 10px;
  background-color: var(--border-color);
  border-radius: var(--border-radius);
  overflow: hidden;
}

.progress-value {
  height: 100%;
  background-color: var(--primary-color);
  transition: width 0.5s ease;
}

/* Related Articles */
.related-articles {
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: var(--spacing-md);
}

.article-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.article-card .card-content {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.article-card .card-text {
  flex: 1;
}

/* Footer */
.footer {
  background-color: var(--dark-background-color);
  color: white;
  padding: var(--spacing-xl) 0;
}

.footer-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
}

.footer-logo {
  margin-bottom: var(--spacing-md);
}

.footer-links h3 {
  color: white;
  margin-top: 0;
  font-size: 1.2rem;
}

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

.footer-links li {
  margin-bottom: var(--spacing-sm);
}

.footer-links a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: color var(--transition-speed);
}

.footer-links a:hover {
  color: white;
  text-decoration: underline;
}

.social-links {
  display: flex;
  gap: var(--spacing-sm);
}

.social-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.1);
  color: white;
  transition: background-color var(--transition-speed);
}

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

.footer-bottom {
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-md);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.9rem;
}

/* Utilities */
.text-center {
  text-align: center;
}

.mb-1 {
  margin-bottom: var(--spacing-sm);
}

.mb-2 {
  margin-bottom: var(--spacing-md);
}

.mb-3 {
  margin-bottom: var(--spacing-lg);
}

.mb-4 {
  margin-bottom: var(--spacing-xl);
}

.mt-1 {
  margin-top: var(--spacing-sm);
}

.mt-2 {
  margin-top: var(--spacing-md);
}

.mt-3 {
  margin-top: var(--spacing-lg);
}

.mt-4 {
  margin-top: var(--spacing-xl);
}

.py-1 {
  padding-top: var(--spacing-sm);
  padding-bottom: var(--spacing-sm);
}

.py-2 {
  padding-top: var(--spacing-md);
  padding-bottom: var(--spacing-md);
}

.py-3 {
  padding-top: var(--spacing-lg);
  padding-bottom: var(--spacing-lg);
}

.py-4 {
  padding-top: var(--spacing-xl);
  padding-bottom: var(--spacing-xl);
}

/* Responsive Styles */
@media (max-width: 992px) {
  .content-container {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    position: static;
    order: -1;
  }
}

@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }
  
  .hero p {
    font-size: 1.1rem;
  }
  
  .hero-buttons {
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
  }
  
  .mobile-menu-btn {
    display: block;
  }
  
  .nav {
    position: fixed;
    top: 60px;
    left: 0;
    width: 100%;
    background-color: var(--background-color);
    box-shadow: var(--box-shadow);
    padding: var(--spacing-md);
    transform: translateY(-100%);
    opacity: 0;
    transition: transform var(--transition-speed), opacity var(--transition-speed);
    z-index: 999;
    pointer-events: none;
  }
  
  .nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }
  
  .nav-list {
    flex-direction: column;
    width: 100%;
  }
  
  .nav-item {
    margin: 0;
    width: 100%;
  }
  
  .nav-link {
    display: block;
    padding: var(--spacing-sm) 0;
    width: 100%;
  }
}

@media (max-width: 576px) {
  :root {
    --base-font-size: 14px;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  .cards, .article-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-container {
    grid-template-columns: 1fr;
  }
}

/* Print Styles */
@media print {
  .header, .footer, .sidebar, .newsletter, .hero {
    display: none;
  }
  
  body {
    font-size: 12pt;
    line-height: 1.5;
    color: #000;
    background-color: #fff;
  }
  
  .container {
    width: 100%;
    max-width: none;
    padding: 0;
    margin: 0;
  }
  
  h1, h2, h3, h4, h5, h6 {
    page-break-after: avoid;
    page-break-inside: avoid;
  }
  
  img {
    max-width: 100% !important;
    page-break-inside: avoid;
  }
  
  pre, blockquote {
    page-break-inside: avoid;
    border: 1px solid #ddd;
  }
  
  a {
    color: #000;
    text-decoration: underline;
  }
  
  .content-container {
    display: block;
  }
}

/* Accessible Focus Styles */
:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Dark Mode Toggle */
.theme-toggle {
  background: none;
  border: none;
  color: var(--text-color);
  cursor: pointer;
  margin-left: var(--spacing-md);
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  transition: background-color var(--transition-speed);
}

.theme-toggle:hover {
  background-color: rgba(0, 0, 0, 0.05);
}

.dark-mode .theme-toggle:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

/* Syntax Highlighting */
.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
  color: #6a9955;
}

.token.punctuation {
  color: #d4d4d4;
}

.token.property,
.token.tag,
.token.boolean,
.token.number,
.token.constant,
.token.symbol,
.token.deleted {
  color: #b5cea8;
}

.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
  color: #ce9178;
}

.token.operator,
.token.entity,
.token.url,
.language-css .token.string,
.style .token.string {
  color: #d4d4d4;
}

.token.atrule,
.token.attr-value,
.token.keyword {
  color: #569cd6;
}

.token.function,
.token.class-name {
  color: #dcdcaa;
}

.token.regex,
.token.important,
.token.variable {
  color: #d16969;
}

.token.important,
.token.bold {
  font-weight: bold;
}

.token.italic {
  font-style: italic;
}

.dark-mode .token.comment,
.dark-mode .token.prolog,
.dark-mode .token.doctype,
.dark-mode .token.cdata {
  color: #6a9955;
}

.dark-mode .token.punctuation {
  color: #d4d4d4;
}

.dark-mode .token.property,
.dark-mode .token.tag,
.dark-mode .token.boolean,
.dark-mode .token.number,
.dark-mode .token.constant,
.dark-mode .token.symbol,
.dark-mode .token.deleted {
  color: #b5cea8;
}

.dark-mode .token.selector,
.dark-mode .token.attr-name,
.dark-mode .token.string,
.dark-mode .token.char,
.dark-mode .token.builtin,
.dark-mode .token.inserted {
  color: #ce9178;
}

/* Animation Classes */
.fade-in {
  animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.slide-in {
  animation: slideIn 0.5s ease-in-out;
}

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

/* Skip to content link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary-color);
  color: white;
  padding: 8px;
  z-index: 100;
  transition: top 0.3s;
}

.skip-link:focus {
  top: 0;
}

/* For the code copy button */
.copy-button {
  position: absolute;
  top: 5px;
  right: 5px;
  background-color: var(--background-color);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 2px 8px;
  font-size: 0.8rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity var(--transition-speed);
}

.code-wrapper {
  position: relative;
}

.code-wrapper:hover .copy-button {
  opacity: 1;
}

.copy-button:hover {
  background-color: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

/* Font size adjustment controls */
.font-controls {
  display: flex;
  align-items: center;
  margin-bottom: var(--spacing-md);
}

.font-control-btn {
  background: none;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-weight: bold;
  margin: 0 var(--spacing-xs);
}

.font-control-btn:hover {
  background-color: var(--code-background);
}

/* Expandable sections */
.expandable-section {
  margin-bottom: var(--spacing-md);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  overflow: hidden;
}

.expandable-header {
  background-color: var(--code-background);
  padding: var(--spacing-sm) var(--spacing-md);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.expandable-content {
  padding: var(--spacing-md);
  display: none;
  border-top: 1px solid var(--border-color);
}

.expandable-section.expanded .expandable-content {
  display: block;
}

.expandable-icon {
  transition: transform var(--transition-speed);
}

.expandable-section.expanded .expandable-icon {
  transform: rotate(180deg);
}

/* Search box */
.search-container {
  position: relative;
  max-width: 300px;
  margin-left: auto;
}

.search-box {
  width: 100%;
  padding: var(--spacing-sm);
  padding-right: 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  transition: width var(--transition-speed);
}

.search-box:focus {
  outline: none;
  border-color: var(--primary-color);
}

.search-btn {
  position: absolute;
  right: 0;
  top: 0;
  height: 100%;
  width: 40px;
  background: none;
  border: none;
  color: var(--light-text-color);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Reading time estimate */
.reading-time {
  display: inline-block;
  color: var(--light-text-color);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-md);
}

.reading-time::before {
  content: "📖 ";
  margin-right: 5px;
}