/* ============================================
   PyMaster - Complete Design System
   ============================================ */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Fira+Code:wght@400;500;600&display=swap');

/* ---------- CSS Custom Properties ---------- */
:root {
  /* Light Mode (default) */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fc;
  --bg-tertiary: #eef1f6;
  --bg-card: #ffffff;
  --bg-code: #1e1e2e;
  --bg-code-inline: #e8eaf0;
  --bg-nav: rgba(255, 255, 255, 0.85);
  --bg-hero-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --bg-accent-gradient: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
  --bg-roadmap: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);

  --text-primary: #1a1a2e;
  --text-secondary: #4a4a6a;
  --text-tertiary: #7a7a9a;
  --text-inverse: #ffffff;
  --text-link: #6366f1;

  --accent-primary: #6366f1;
  --accent-secondary: #8b5cf6;
  --accent-green: #10b981;
  --accent-orange: #f59e0b;
  --accent-red: #ef4444;
  --accent-blue: #3b82f6;
  --accent-pink: #ec4899;
  --accent-cyan: #06b6d4;

  --border-color: #e2e8f0;
  --border-radius: 12px;
  --border-radius-sm: 8px;
  --border-radius-lg: 20px;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 60px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.15);

  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-code: 'Fira Code', 'Consolas', monospace;

  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;

  --container-max: 1200px;
  --nav-height: 70px;
}

/* ---------- Dark Mode ---------- */
[data-theme="dark"] {
  --bg-primary: #0f0f1a;
  --bg-secondary: #1a1a2e;
  --bg-tertiary: #25253d;
  --bg-card: #1e1e32;
  --bg-code: #0d0d1a;
  --bg-code-inline: #2a2a44;
  --bg-nav: rgba(15, 15, 26, 0.9);
  --bg-hero-gradient: linear-gradient(135deg, #1a1a2e 0%, #2d1b69 100%);
  --bg-roadmap: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);

  --text-primary: #e8e8f0;
  --text-secondary: #a8a8c8;
  --text-tertiary: #6a6a8a;
  --text-link: #818cf8;

  --border-color: #2e2e4a;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 60px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.25);
}

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

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

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  transition: background var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

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

a:hover {
  color: var(--accent-secondary);
}

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

::selection {
  background: var(--accent-primary);
  color: white;
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
  width: 8px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--accent-primary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-secondary);
}

/* ---------- Container ---------- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

.container-narrow {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   NAVIGATION
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--bg-nav);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  height: var(--nav-height);
  transition: all var(--transition-normal);
}

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

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  text-decoration: none;
}

.nav-brand .logo-icon {
  font-size: 1.8rem;
}

.nav-brand span {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: var(--border-radius-sm);
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: all var(--transition-fast);
  position: relative;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent-primary);
  background: rgba(99, 102, 241, 0.08);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 3px;
  background: var(--accent-primary);
  border-radius: 2px;
}

.theme-toggle {
  width: 44px;
  height: 44px;
  border: none;
  border-radius: 50%;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 1.2rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--accent-primary);
  color: white;
  transform: rotate(30deg);
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 8px;
}

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

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    transform: translateY(-120%);
    transition: transform var(--transition-normal);
    box-shadow: var(--shadow-lg);
  }

  .nav-links.open {
    transform: translateY(0);
  }

  .nav-links a {
    width: 100%;
    padding: 12px 16px;
  }
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-hero-gradient);
  position: relative;
  overflow: hidden;
  padding-top: var(--nav-height);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Ccircle cx='30' cy='30' r='2'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
  text-align: center;
  position: relative;
  z-index: 1;
  padding: 40px 20px;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 900;
  color: white;
  line-height: 1.1;
  margin-bottom: 20px;
  text-shadow: 0 2px 40px rgba(0, 0, 0, 0.2);
}

.hero h1 .highlight {
  background: linear-gradient(135deg, #43e97b, #38f9d7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  color: rgba(255, 255, 255, 0.85);
  max-width: 650px;
  margin: 0 auto 40px;
  line-height: 1.6;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast);
  text-decoration: none;
  font-family: var(--font-body);
}

.btn-primary {
  background: white;
  color: #6366f1;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2);
  color: #6366f1;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.15);
  color: white;
  border: 2px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-3px);
  color: white;
}

.btn-accent {
  background: var(--accent-primary);
  color: white;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.3);
}

.btn-accent:hover {
  background: var(--accent-secondary);
  transform: translateY(-2px);
}

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

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

/* Floating shapes */
.floating-shapes {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.floating-shapes .shape {
  position: absolute;
  border-radius: 50%;
  opacity: 0.1;
  animation: float 6s ease-in-out infinite;
}

.floating-shapes .shape:nth-child(1) {
  width: 200px;
  height: 200px;
  background: #43e97b;
  top: 10%;
  left: 5%;
  animation-delay: 0s;
}

.floating-shapes .shape:nth-child(2) {
  width: 150px;
  height: 150px;
  background: #38f9d7;
  top: 60%;
  right: 10%;
  animation-delay: 2s;
}

.floating-shapes .shape:nth-child(3) {
  width: 100px;
  height: 100px;
  background: #f59e0b;
  bottom: 20%;
  left: 20%;
  animation-delay: 4s;
}

.floating-shapes .shape:nth-child(4) {
  width: 180px;
  height: 180px;
  background: #ec4899;
  top: 30%;
  right: 25%;
  animation-delay: 1s;
}

@keyframes float {

  0%,
  100% {
    transform: translateY(0) rotate(0deg);
  }

  50% {
    transform: translateY(-20px) rotate(5deg);
  }
}

/* ============================================
   ROADMAP
   ============================================ */
.roadmap-section {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-header .badge {
  display: inline-block;
  padding: 6px 18px;
  border-radius: 50px;
  background: rgba(99, 102, 241, 0.1);
  color: var(--accent-primary);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 16px;
}

.section-header h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  margin-bottom: 16px;
  line-height: 1.2;
}

.section-header p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.roadmap {
  display: flex;
  justify-content: center;
  gap: 0;
  position: relative;
  flex-wrap: wrap;
  padding: 20px 0;
}

.roadmap-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 30px 20px;
  position: relative;
  flex: 1;
  min-width: 200px;
  max-width: 300px;
}

.roadmap-step .step-icon {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  margin-bottom: 20px;
  position: relative;
  z-index: 2;
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-fast);
}

.roadmap-step:hover .step-icon {
  transform: scale(1.1);
}

.roadmap-step.beginner .step-icon {
  background: linear-gradient(135deg, #10b981, #34d399);
}

.roadmap-step.intermediate .step-icon {
  background: linear-gradient(135deg, #f59e0b, #fbbf24);
}

.roadmap-step.advanced .step-icon {
  background: linear-gradient(135deg, #ef4444, #f87171);
}

.roadmap-step h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.roadmap-step p {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.roadmap-connector {
  position: absolute;
  top: 70px;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-green), var(--accent-primary));
  right: -30px;
  z-index: 1;
}

@media (max-width: 768px) {
  .roadmap {
    flex-direction: column;
    align-items: center;
  }

  .roadmap-connector {
    display: none;
  }
}

/* ============================================
   FEATURE CARDS
   ============================================ */
.features-section {
  padding: 100px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 36px;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
  transform: scaleX(0);
  transition: transform var(--transition-normal);
  transform-origin: left;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.feature-card:hover::before {
  transform: scaleX(1);
}

.feature-card .card-icon {
  width: 60px;
  height: 60px;
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.feature-card .card-icon.green {
  background: rgba(16, 185, 129, 0.12);
}

.feature-card .card-icon.blue {
  background: rgba(59, 130, 246, 0.12);
}

.feature-card .card-icon.purple {
  background: rgba(139, 92, 246, 0.12);
}

.feature-card .card-icon.orange {
  background: rgba(245, 158, 11, 0.12);
}

.feature-card .card-icon.pink {
  background: rgba(236, 72, 153, 0.12);
}

.feature-card .card-icon.cyan {
  background: rgba(6, 182, 212, 0.12);
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ============================================
   PAGE CONTENT LAYOUT
   ============================================ */
.page-hero {
  padding: 120px 0 60px;
  text-align: center;
  background: var(--bg-hero-gradient);
  color: white;
  position: relative;
}

.page-hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900;
  margin-bottom: 16px;
}

.page-hero p {
  font-size: 1.2rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

.content-section {
  padding: 80px 0;
}

/* ============================================
   TOPIC CARDS / LESSON CARDS
   ============================================ */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
  margin-top: 40px;
}

.topic-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 32px;
  transition: all var(--transition-normal);
  cursor: pointer;
}

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

.topic-card .topic-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  font-weight: 700;
  font-size: 0.9rem;
  margin-bottom: 16px;
  background: rgba(99, 102, 241, 0.1);
  color: var(--accent-primary);
}

.topic-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.topic-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.topic-card .topic-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.topic-card .tag {
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
}

/* ============================================
   LESSON CONTENT (Expanded topic)
   ============================================ */
.lesson {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  margin-bottom: 32px;
  overflow: hidden;
}

.lesson-header {
  padding: 24px 32px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 16px;
  transition: background var(--transition-fast);
}

.lesson-header:hover {
  background: var(--bg-secondary);
}

.lesson-header .lesson-num {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: white;
}

.lesson-header h2 {
  font-size: 1.3rem;
  font-weight: 700;
  flex: 1;
}

.lesson-header .toggle-icon {
  font-size: 1.2rem;
  color: var(--text-tertiary);
  transition: transform var(--transition-fast);
}

.lesson.open .lesson-header .toggle-icon {
  transform: rotate(180deg);
}

.lesson-body {
  padding: 0 32px 32px;
  display: none;
}

.lesson.open .lesson-body {
  display: block;
}

.lesson-body h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 28px 0 12px;
  color: var(--accent-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.lesson-body h3:first-child {
  margin-top: 0;
}

.lesson-body p,
.lesson-body li {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.8;
  margin-bottom: 12px;
}

.lesson-body ul,
.lesson-body ol {
  padding-left: 24px;
  margin-bottom: 16px;
}

.lesson-body li {
  margin-bottom: 6px;
}

.lesson-body strong {
  color: var(--text-primary);
}

/* Info/Tip/Warning boxes */
.info-box {
  padding: 16px 20px;
  border-radius: var(--border-radius-sm);
  margin: 16px 0;
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 0.95rem;
}

.info-box.tip {
  background: rgba(16, 185, 129, 0.08);
  border-left: 4px solid var(--accent-green);
}

.info-box.note {
  background: rgba(59, 130, 246, 0.08);
  border-left: 4px solid var(--accent-blue);
}

.info-box.warning {
  background: rgba(245, 158, 11, 0.08);
  border-left: 4px solid var(--accent-orange);
}

.info-box.hinglish {
  background: rgba(139, 92, 246, 0.08);
  border-left: 4px solid var(--accent-secondary);
}

.info-box .icon {
  font-size: 1.2rem;
  flex-shrink: 0;
  margin-top: 2px;
}

/* ============================================
   CODE BLOCKS
   ============================================ */
.code-block {
  position: relative;
  margin: 16px 0;
  border-radius: var(--border-radius);
  overflow: hidden;
  background: var(--bg-code);
  box-shadow: var(--shadow-md);
}

.code-block .code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px;
  background: rgba(255, 255, 255, 0.05);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.code-block .code-lang {
  font-family: var(--font-code);
  font-size: 0.8rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.5);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.code-block .copy-btn {
  padding: 4px 12px;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.05);
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-body);
}

.code-block .copy-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  color: white;
}

.code-block .copy-btn.copied {
  background: var(--accent-green);
  color: white;
  border-color: var(--accent-green);
}

.code-block pre {
  padding: 20px;
  margin: 0;
  overflow-x: auto;
}

.code-block pre code {
  font-family: var(--font-code);
  font-size: 0.9rem;
  line-height: 1.7;
  color: #e4e4e7;
}

/* Inline code */
code:not([class*="language-"]) {
  font-family: var(--font-code);
  font-size: 0.88em;
  background: var(--bg-code-inline);
  padding: 2px 8px;
  border-radius: 4px;
  color: var(--accent-primary);
}

/* Output block */
.output-block {
  margin: 8px 0 16px;
  padding: 16px 20px;
  border-radius: var(--border-radius-sm);
  background: rgba(16, 185, 129, 0.06);
  border: 1px solid rgba(16, 185, 129, 0.15);
  font-family: var(--font-code);
  font-size: 0.9rem;
  color: var(--accent-green);
}

.output-block .output-label {
  font-family: var(--font-body);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-green);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ============================================
   PRACTICE SECTION
   ============================================ */
.practice-box {
  background: var(--bg-card);
  border: 2px solid var(--accent-primary);
  border-radius: var(--border-radius-lg);
  padding: 32px;
  margin: 32px 0;
}

.practice-box h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--accent-primary);
}

.practice-question {
  padding: 16px 20px;
  border-radius: var(--border-radius-sm);
  background: var(--bg-secondary);
  margin-bottom: 12px;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: 1px solid transparent;
}

.practice-question:hover {
  border-color: var(--accent-primary);
}

.practice-question .q-num {
  font-weight: 700;
  color: var(--accent-primary);
  margin-right: 8px;
}

.practice-question .difficulty {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 50px;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  margin-left: 8px;
}

.difficulty.easy {
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-green);
}

.difficulty.medium {
  background: rgba(245, 158, 11, 0.12);
  color: var(--accent-orange);
}

.difficulty.hard {
  background: rgba(239, 68, 68, 0.12);
  color: var(--accent-red);
}

.practice-answer {
  display: none;
  margin-top: 12px;
  padding: 16px;
  background: var(--bg-tertiary);
  border-radius: var(--border-radius-sm);
}

.practice-question.show-answer .practice-answer {
  display: block;
}

/* ============================================
   CODE PLAYGROUND
   ============================================ */
.playground {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.playground-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.playground-header h3 {
  font-size: 1.1rem;
  font-weight: 600;
}

.playground-editor {
  min-height: 250px;
}

.playground-editor textarea {
  width: 100%;
  min-height: 250px;
  padding: 20px;
  font-family: var(--font-code);
  font-size: 0.95rem;
  line-height: 1.6;
  background: var(--bg-code);
  color: #e4e4e7;
  border: none;
  resize: vertical;
  outline: none;
}

.playground-output {
  padding: 20px;
  min-height: 80px;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  font-family: var(--font-code);
  font-size: 0.9rem;
  color: var(--accent-green);
}

.run-btn {
  padding: 8px 24px;
  border-radius: 8px;
  border: none;
  background: var(--accent-green);
  color: white;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-body);
}

.run-btn:hover {
  background: #059669;
  transform: translateY(-1px);
}

/* ============================================
   PROJECT CARDS
   ============================================ */
.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.project-card .project-img {
  height: 180px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  position: relative;
}

.project-card .project-img.beginner-bg {
  background: linear-gradient(135deg, #10b981, #34d399);
}

.project-card .project-img.intermediate-bg {
  background: linear-gradient(135deg, #f59e0b, #fbbf24);
}

.project-card .project-img.advanced-bg {
  background: linear-gradient(135deg, #ef4444, #f87171);
}

.project-card .project-body {
  padding: 24px;
}

.project-card .project-body h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.project-card .project-body p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.project-card .project-level {
  display: inline-block;
  padding: 4px 14px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
}

.project-level.beginner {
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-green);
}

.project-level.intermediate {
  background: rgba(245, 158, 11, 0.12);
  color: var(--accent-orange);
}

.project-level.advanced {
  background: rgba(239, 68, 68, 0.12);
  color: var(--accent-red);
}

/* ============================================
   RESOURCES
   ============================================ */
.resource-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 32px;
  transition: all var(--transition-normal);
}

.resource-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.resource-card .res-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 16px;
  background: rgba(99, 102, 241, 0.1);
}

.resource-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.resource-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

/* ============================================
   TABS
   ============================================ */
.tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 32px;
  background: var(--bg-secondary);
  padding: 4px;
  border-radius: var(--border-radius);
  overflow-x: auto;
}

.tab-btn {
  padding: 12px 24px;
  border: none;
  border-radius: var(--border-radius-sm);
  background: transparent;
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
  font-family: var(--font-body);
}

.tab-btn.active {
  background: var(--accent-primary);
  color: white;
  box-shadow: var(--shadow-sm);
}

.tab-btn:hover:not(.active) {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   TABLES
   ============================================ */
.styled-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.styled-table thead {
  background: var(--accent-primary);
  color: white;
}

.styled-table th {
  padding: 14px 20px;
  text-align: left;
  font-weight: 600;
  font-size: 0.9rem;
}

.styled-table td {
  padding: 12px 20px;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.9rem;
}

.styled-table tr:last-child td {
  border-bottom: none;
}

.styled-table tbody tr {
  background: var(--bg-card);
  transition: background var(--transition-fast);
}

.styled-table tbody tr:hover {
  background: var(--bg-secondary);
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  padding: 60px 0 30px;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 16px;
}

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

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-col a:hover {
  color: var(--accent-primary);
}

.footer-bottom {
  text-align: center;
  padding-top: 30px;
  border-top: 1px solid var(--border-color);
  color: var(--text-tertiary);
  font-size: 0.85rem;
}

/* ============================================
   SCROLL ANIMATIONS
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
  text-align: center;
}

.text-gradient {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.mt-1 {
  margin-top: 8px;
}

.mt-2 {
  margin-top: 16px;
}

.mt-3 {
  margin-top: 24px;
}

.mt-4 {
  margin-top: 32px;
}

.mb-1 {
  margin-bottom: 8px;
}

.mb-2 {
  margin-bottom: 16px;
}

.mb-3 {
  margin-bottom: 24px;
}

.mb-4 {
  margin-bottom: 32px;
}

.flex {
  display: flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.gap-1 {
  gap: 8px;
}

.gap-2 {
  gap: 16px;
}

.gap-3 {
  gap: 24px;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {

  .features-grid,
  .topic-grid {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  .hero {
    min-height: 90vh;
  }

  .hero h1 {
    font-size: 2.2rem;
  }

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

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

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

  .lesson-header {
    padding: 16px 20px;
  }

  .lesson-body {
    padding: 0 20px 20px;
  }

  .tabs {
    gap: 2px;
  }

  .tab-btn {
    padding: 10px 16px;
    font-size: 0.85rem;
  }

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

  .section-header h2 {
    font-size: 1.8rem;
  }
}

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

  .tabs {
    flex-direction: column;
  }

  .tab-btn {
    width: 100%;
    text-align: center;
  }
}

/* ============================================
   PRINT STYLES
   ============================================ */
@media print {

  .navbar,
  .footer,
  .theme-toggle,
  .mobile-toggle {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .hero {
    min-height: auto;
    padding: 40px 0;
  }
}

/* ============================================
   LESSON PROGRESS & NAVIGATION
   ============================================ */
.progress-container {
  margin: 20px 0 40px;
  background: var(--bg-card);
  padding: 20px;
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.progress-label {
  display: flex;
  justify-content: space-between;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
  font-size: 0.95rem;
}

.progress-bar {
  height: 10px;
  background: var(--bg-tertiary);
  border-radius: 20px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
  width: 0%;
  transition: width 0.5s ease;
}

.lesson-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 30px;
  padding-top: 20px;
  border-top: 1px solid var(--border-color);
}

.btn-prev,
.btn-next {
  padding: 10px 20px;
  border-radius: var(--border-radius-sm);
  border: none;
  cursor: pointer;
  font-weight: 600;
  transition: all var(--transition-fast);
  font-family: var(--font-body);
}

.btn-prev {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
}

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

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

.lesson.completed .lesson-header h2::after {
  content: ' ✓';
  color: var(--accent-green);
  margin-left: 8px;
}

/* ============================================
   LESSON SEARCH
   ============================================ */
.search-container {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-card);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 12px 20px;
  margin-bottom: 24px;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-container:focus-within {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.12);
}

.search-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
  opacity: 0.5;
}

.search-input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text-primary);
}

.search-input::placeholder {
  color: var(--text-tertiary);
}

.search-clear {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: none;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.search-clear:hover {
  background: var(--accent-red);
  color: white;
}

.search-no-results {
  text-align: center;
  padding: 48px 20px;
  color: var(--text-tertiary);
}

.search-no-results .no-results-icon {
  font-size: 3rem;
  margin-bottom: 12px;
  opacity: 0.5;
}

.search-no-results p {
  font-size: 1.05rem;
  font-weight: 500;
}