/**
 * ULTIMATE PHYSICAL GEOGRAPHY EXPERIENCE
 * Ultra-modern design with topic-specific backgrounds and glassmorphism
 * Enhanced with real Unsplash images for all 10 geography topics
 */

/* ========================================
   CSS VARIABLES - VIBRANT THEME BASE
======================================== */

:root {
  /* Typography */
  --font-primary: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-secondary: 'Inter', 'Lato', 'Helvetica Neue', Arial, sans-serif;
  --font-display: 'Montserrat', var(--font-primary);
  --font-body: var(--font-secondary);
  --font-mono: 'Monaco', 'Courier New', monospace;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --spacing-3xl: 6rem;
  
  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;
  --radius-2xl: 3rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 0.6s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  
  /* Z-index */
  --z-background: -1;
  --z-base: 1;
  --z-content: 10;
  --z-dropdown: 100;
  --z-sticky: 500;
  --z-header: 1000;
  --z-nav: 1000;
  --z-modal: 2000;
  --z-preloader: 9999;
  
  /* Base colors (fallback) */
  --sky-day: linear-gradient(180deg, #e0f7fa 0%, #b2ebf2 100%);
  --sky-night: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
  --ice-light: #e0f2fe;
  --ice-medium: #7dd3fc;
  --ice-dark: #0369a1;
  --glacier-blue: #0284c7;
  --accent-gold: #f4d03f;
  --frost: rgba(255, 255, 255, 0.05);
  --bg-glass: rgba(255, 255, 255, 0.03);
  --border-light: rgba(255, 255, 255, 0.1);
  --border-frost: rgba(255, 255, 255, 0.15);
  --text-light: #f1f5f9;
  --text-subtle: #94a3b8;
  --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-medium: 0 8px 24px rgba(0, 0, 0, 0.15);
  --shadow-strong: 0 20px 50px rgba(0, 0, 0, 0.25);
  --shadow-ice: 0 0 30px rgba(100, 180, 255, 0.3);
}

/* ========================================
   MOUNTAINS THEME - ORIGINAL
======================================== */

.mountains-theme {
  /* Primary Colors - Electric & Bold */
  --primary: #6366f1;
  --primary-dark: #4338ca;
  --primary-light: #818cf8;
  --primary-glow: rgba(99, 102, 241, 0.5);
  
  /* Accent Colors - Vibrant Spectrum */
  --accent: #f59e0b;
  --accent-warm: #ff6b6b;
  --accent-cool: #00d2ff;
  --accent-pink: #ec4899;
  --accent-green: #10b981;
  
  /* Backgrounds - Dark Premium */
  --bg-dark: #0f172a;
  --bg-darker: #020617;
  --bg-darkest: #000000;
  --bg-card: rgba(30, 41, 59, 0.7);
  --bg-card-hover: rgba(51, 65, 85, 0.8);
  
  /* Glass Effects */
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-shadow: rgba(0, 0, 0, 0.3);
  
  /* Text Colors */
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-dark: #1e293b;
  
  /* Gradients - Spectacular */
  --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
  --gradient-sunset: linear-gradient(135deg, #ff6b6b 0%, #f59e0b 50%, #feca57 100%);
  --gradient-arctic: linear-gradient(135deg, #00d2ff 0%, #3a7bd5 50%, #00d2ff 100%);
  --gradient-card: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(236, 72, 153, 0.1) 100%);
  --gradient-glow: radial-gradient(circle at center, var(--primary-glow) 0%, transparent 70%);
  
  /* Shadows - Dramatic */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 30px 90px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px var(--primary-glow);
  --shadow-neon: 0 0 20px var(--accent-pink), 0 0 40px var(--accent-pink);
  
  /* Branch color for mountains */
  --branch-color: #6366f1;
}

/* ========================================
   TOPIC-SPECIFIC BACKGROUND IMAGES
   Using Real Unsplash Photos
======================================== */

/* MOUNTAINS - Snow-capped peaks */
.mountains-theme .concept-hero .hero-background,
.mountains-theme .topic-card .topic-image,
.mountains-theme .example-image[style*="mountains"],
.mountains-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1506905925346-21bda4d32df4?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* RIVERS - Flowing water and riverscapes */
.rivers-theme .concept-hero .hero-background,
.rivers-theme .topic-card .topic-image,
.rivers-theme .example-image[style*="river"],
.rivers-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1439066615861-d1af74d74000?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* VOLCANOES - Erupting or dormant volcanoes */
.volcanoes-theme .concept-hero .hero-background,
.volcanoes-theme .topic-card .topic-image,
.volcanoes-theme .example-image[style*="volcano"],
.volcanoes-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1603487742131-4160ec999306?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* WATERFALLS - Cascading water */
.waterfalls-theme .concept-hero .hero-background,
.waterfalls-theme .topic-card .topic-image,
.waterfalls-theme .example-image[style*="waterfall"],
.waterfalls-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1432405972618-c60b0225b8f9?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* OCEANS - Deep blue waters and waves */
.oceans-theme .concept-hero .hero-background,
.oceans-theme .topic-card .topic-image,
.oceans-theme .example-image[style*="ocean"],
.oceans-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1505142468610-359e7d316be0?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* CORAL REEFS - Underwater coral formations */
.coral-reefs-theme .concept-hero .hero-background,
.coral-reefs-theme .topic-card .topic-image,
.coral-reefs-theme .example-image[style*="coral"],
.coral-reefs-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1559827260-dc66d52bef19?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* ISLANDS - Tropical paradise views */
.islands-theme .concept-hero .hero-background,
.islands-theme .topic-card .topic-image,
.islands-theme .example-image[style*="island"],
.islands-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1559827260-dc66d52bef19?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* LAKES - Calm water bodies */
.lakes-theme .concept-hero .hero-background,
.lakes-theme .topic-card .topic-image,
.lakes-theme .example-image[style*="lake"],
.lakes-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1506905925346-21bda4d32df4?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* DESERTS - Sand dunes and arid landscapes */
.deserts-theme .concept-hero .hero-background,
.deserts-theme .topic-card .topic-image,
.deserts-theme .example-image[style*="desert"],
.deserts-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1509316785289-025f5b846b35?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* FORESTS - Dense tree coverage */
.forests-theme .concept-hero .hero-background,
.forests-theme .topic-card .topic-image,
.forests-theme .example-image[style*="forest"],
.forests-theme .range-image {
  background-image: url('https://images.unsplash.com/photo-1441974231531-c6227db76b6e?w=1920&q=90');
  background-size: cover;
  background-position: center;
}

/* ========================================
   ENHANCED OVERLAY SYSTEM
   For Better Text Readability
======================================== */

/* Mountains overlay - Purple tint */
.mountains-theme .hero-overlay,
.mountains-theme .example-overlay,
.mountains-theme .range-overlay,
.mountains-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(15, 23, 42, 0.75) 0%,
    rgba(99, 102, 241, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Rivers overlay - Blue tint */
.rivers-theme .hero-overlay,
.rivers-theme .example-overlay,
.rivers-theme .range-overlay,
.rivers-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(3, 4, 94, 0.75) 0%,
    rgba(0, 119, 182, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Volcanoes overlay - Orange/Red tint */
.volcanoes-theme .hero-overlay,
.volcanoes-theme .example-overlay,
.volcanoes-theme .range-overlay,
.volcanoes-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(26, 10, 0, 0.75) 0%,
    rgba(255, 107, 53, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Waterfalls overlay - Cyan tint */
.waterfalls-theme .hero-overlay,
.waterfalls-theme .example-overlay,
.waterfalls-theme .range-overlay,
.waterfalls-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(0, 77, 90, 0.75) 0%,
    rgba(0, 188, 212, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Oceans overlay - Deep blue */
.oceans-theme .hero-overlay,
.oceans-theme .example-overlay,
.oceans-theme .range-overlay,
.oceans-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(0, 29, 61, 0.75) 0%,
    rgba(4, 102, 200, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Coral Reefs overlay - Pink tint */
.coral-reefs-theme .hero-overlay,
.coral-reefs-theme .example-overlay,
.coral-reefs-theme .range-overlay,
.coral-reefs-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(61, 26, 40, 0.75) 0%,
    rgba(255, 99, 146, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Islands overlay - Green/Teal tint */
.islands-theme .hero-overlay,
.islands-theme .example-overlay,
.islands-theme .range-overlay,
.islands-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(0, 61, 50, 0.75) 0%,
    rgba(6, 214, 160, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Lakes overlay - Blue tint */
.lakes-theme .hero-overlay,
.lakes-theme .example-overlay,
.lakes-theme .range-overlay,
.lakes-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(0, 34, 51, 0.75) 0%,
    rgba(0, 119, 182, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Deserts overlay - Sand/Orange tint */
.deserts-theme .hero-overlay,
.deserts-theme .example-overlay,
.deserts-theme .range-overlay,
.deserts-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(61, 35, 20, 0.75) 0%,
    rgba(244, 162, 97, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

/* Forests overlay - Green tint */
.forests-theme .hero-overlay,
.forests-theme .example-overlay,
.forests-theme .range-overlay,
.forests-theme .topic-overlay {
  background: linear-gradient(
    180deg,
    rgba(5, 46, 22, 0.75) 0%,
    rgba(16, 185, 129, 0.4) 50%,
    rgba(0, 0, 0, 0.85) 100%
  );
}

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

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

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
}

body.concept-page {
  font-family: var(--font-secondary);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background: var(--bg-darker);
  overflow-x: hidden;
  position: relative;
}

/* Animated background particles */
body.concept-page::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(236, 72, 153, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 40% 90%, rgba(245, 158, 11, 0.05) 0%, transparent 50%);
  z-index: var(--z-background);
  pointer-events: none;
  animation: particleFloat 20s ease-in-out infinite;
}

@keyframes particleFloat {
  0%, 100% { opacity: 0.3; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(1.1); }
}

@keyframes gentleFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-primary);
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-base);
}

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

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

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* ========================================
   PRELOADER - EPIC LOADING
======================================== */

.preloader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--bg-darkest);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-preloader);
  transition: opacity 0.5s, visibility 0.5s;
}

.preloader.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

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

.loader-spinner {
  position: relative;
  width: 120px;
  height: 120px;
  margin: 0 auto 2rem;
}

.spinner-ring {
  position: absolute;
  width: 100%;
  height: 100%;
  border: 4px solid transparent;
  border-radius: 50%;
  animation: spin 1.5s cubic-bezier(0.68, -0.55, 0.265, 1.55) infinite;
}

.spinner-ring:nth-child(1) {
  border-top-color: var(--primary);
  animation-delay: 0s;
}

.spinner-ring:nth-child(2) {
  width: 80%;
  height: 80%;
  top: 10%;
  left: 10%;
  border-top-color: var(--accent);
  animation-delay: 0.2s;
}

.spinner-ring:nth-child(3) {
  width: 60%;
  height: 60%;
  top: 20%;
  left: 20%;
  border-top-color: var(--accent-pink);
  animation-delay: 0.4s;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.preloader-text {
  font-size: 1.25rem;
  font-weight: 600;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.6; }
  50% { opacity: 1; }
}

/* Globe loader for hub page */
.globe-loader {
  position: relative;
  width: 120px;
  height: 120px;
  margin: 0 auto 2rem;
}

.globe {
  font-size: 6rem;
  animation: globeSpin 3s linear infinite;
}

@keyframes globeSpin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* ========================================
   NAVIGATION - FUTURISTIC
======================================== */

.main-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: var(--bg-card);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--glass-border);
  box-shadow: var(--shadow-md);
  z-index: var(--z-nav);
  transition: transform 0.3s, background 0.3s;
}

.main-nav.scrolled {
  background: rgba(15, 23, 42, 0.95);
  box-shadow: var(--shadow-lg);
}

.main-nav.hidden {
  transform: translateY(-100%);
}

.nav-container {
  max-width: 1600px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.5rem;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transition: var(--transition-base);
}

.nav-logo:hover {
  transform: scale(1.05);
  filter: drop-shadow(0 0 20px var(--primary-glow));
}

.logo-icon {
  font-size: 2rem;
  filter: drop-shadow(0 0 10px var(--primary-glow));
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9375rem;
  transition: var(--transition-base);
  position: relative;
  overflow: hidden;
}

.nav-link::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--gradient-card);
  transition: var(--transition-base);
  z-index: -1;
}

.nav-link:hover::before {
  left: 0;
}

.nav-link:hover {
  color: var(--text-primary);
  transform: translateY(-2px);
}

.nav-link.active {
  background: var(--gradient-hero);
  color: white;
  box-shadow: var(--shadow-glow);
}

.nav-icon {
  font-size: 1.25rem;
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 0.5rem;
  cursor: pointer;
}

.mobile-menu-toggle span {
  width: 28px;
  height: 3px;
  background: var(--text-primary);
  border-radius: 3px;
  transition: var(--transition-base);
}

.mobile-menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
}

.mobile-menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* Mobile menu */
.mobile-menu {
  position: fixed;
  top: 70px;
  left: 0;
  width: 100%;
  max-height: 0;
  overflow: hidden;
  background: var(--bg-darker);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--glass-border);
  transition: max-height 0.3s ease;
  z-index: 999;
}

.mobile-menu.active {
  max-height: 500px;
}

.mobile-menu-content {
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.mobile-nav-link {
  padding: 1rem 1.5rem;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition-base);
  border: 1px solid var(--glass-border);
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
  background: var(--gradient-hero);
  color: white;
  border-color: transparent;
}

/* Navigation actions */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.theme-toggle {
  width: 45px;
  height: 45px;
  border-radius: 50%;
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-base);
}

.theme-toggle:hover {
  background: var(--gradient-hero);
  transform: scale(1.1);
  box-shadow: var(--shadow-glow);
}

.theme-icon {
  font-size: 1.5rem;
}

/* ========================================
   HERO SECTION - CINEMATIC
======================================== */

.concept-hero {
  position: relative;
  height: 85vh;
  min-height: 600px;
  max-height: 900px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  margin-top: 70px;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  image-rendering: -webkit-optimize-contrast;
  image-rendering: crisp-edges;
  animation: gentleZoom 30s ease-in-out infinite alternate;
}

@keyframes gentleZoom {
  0% { transform: scale(1); }
  100% { transform: scale(1.03); }
}

.hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  /* Overlays defined per theme above */
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 1000px;
  padding: 0 2rem;
  animation: heroFadeIn 1s ease-out;
}

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

.breadcrumb {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  font-size: 0.9375rem;
  margin-bottom: 2rem;
  opacity: 0.9;
}

.breadcrumb a {
  color: var(--text-secondary);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-full);
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  transition: var(--transition-base);
}

.breadcrumb a:hover {
  background: var(--glass-bg);
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.breadcrumb .separator {
  opacity: 0.5;
  font-size: 1.25rem;
}

.hero-title {
  font-size: clamp(3rem, 8vw, 5.5rem);
  font-weight: 900;
  margin-bottom: 1.5rem;
  line-height: 1.1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
  background: linear-gradient(135deg, #ffffff 0%, #cbd5e1 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: titleGlow 3s ease-in-out infinite alternate;
}

@keyframes titleGlow {
  from { filter: drop-shadow(0 0 20px rgba(99, 102, 241, 0.3)); }
  to { filter: drop-shadow(0 0 40px rgba(236, 72, 153, 0.5)); }
}

.topic-icon {
  font-size: 1em;
  filter: drop-shadow(0 0 30px var(--accent-warm));
  animation: iconFloat 3s ease-in-out infinite;
}

@keyframes iconFloat {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-10px) rotate(5deg); }
}

.hero-tagline {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  font-weight: 300;
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
  margin-bottom: 3rem;
}

/* Scroll indicator */
.hero-content::after {
  content: '↓';
  position: absolute;
  bottom: -4rem;
  left: 50%;
  transform: translateX(-50%);
  font-size: 2rem;
  color: var(--text-secondary);
  animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(-10px); }
}

/* Hero stats for hub page */
.hero-stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  margin: 3rem 0;
  flex-wrap: wrap;
}

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

.stat-value {
  display: block;
  font-size: 3rem;
  font-weight: 800;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.5rem;
}

.stat-label {
  font-size: 0.95rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Hero actions */
.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 2rem;
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 1rem;
  transition: var(--transition-bounce);
  text-decoration: none;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--gradient-hero);
  color: white;
  box-shadow: var(--shadow-lg);
}

.btn-primary:hover {
  transform: translateY(-5px) scale(1.05);
  box-shadow: var(--shadow-neon);
}

.btn-secondary {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  color: var(--text-primary);
  border-color: var(--glass-border);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--primary);
  transform: translateY(-5px);
}

/* Scroll indicator */
.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.mouse {
  width: 26px;
  height: 40px;
  border: 2px solid var(--text-secondary);
  border-radius: 20px;
  margin: 0 auto 0.5rem;
  position: relative;
}

.wheel {
  width: 4px;
  height: 8px;
  background: var(--text-secondary);
  border-radius: 2px;
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  animation: scroll 2s infinite;
}

@keyframes scroll {
  0%, 100% { opacity: 0; top: 8px; }
  50% { opacity: 1; top: 16px; }
}

/* ========================================
   MAIN CONTENT AREA
======================================== */

.concept-main {
  background: var(--bg-darker);
  padding: var(--spacing-3xl) 0;
  position: relative;
}

.content-section {
  padding: var(--spacing-xl) 0;
}

.section-intro {
  font-size: clamp(1.125rem, 2vw, 1.375rem);
  line-height: 1.8;
  color: var(--text-secondary);
  max-width: 900px;
  margin: 0 auto 4rem;
  text-align: center;
  padding: 2rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-md);
}

/* ========================================
   KEY POINTS GRID - GLASSMORPHIC CARDS
======================================== */

.key-points-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
  margin-bottom: 4rem;
}

.key-point-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: 2.5rem;
  box-shadow: var(--shadow-md);
  transition: var(--transition-slow);
  position: relative;
  overflow: hidden;
}

.key-point-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--gradient-hero);
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition-slow);
}

.key-point-card:hover {
  transform: translateY(-10px) rotateX(2deg);
  box-shadow: 
    var(--shadow-xl),
    0 0 60px var(--primary-glow);
  border-color: var(--primary);
}

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

.point-icon {
  font-size: 4rem;
  margin-bottom: 1.5rem;
  display: block;
  filter: drop-shadow(0 0 20px var(--accent));
  animation: iconPulse 2s ease-in-out infinite;
}

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

.point-label {
  font-size: 1.5rem;
  font-weight: 700;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 1rem;
}

.point-text {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  line-height: 1.6;
}

.point-detail {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ========================================
   COMPARISON TABLE - MODERN & INTERACTIVE
======================================== */

.comparison-section {
  margin: 4rem 0;
  padding: 3rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
}

.comparison-title {
  font-size: 2.5rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 3rem;
  background: var(--gradient-sunset);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.comparison-table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-lg);
}

.comparison-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 1rem;
}

.comparison-table thead {
  background: var(--gradient-hero);
  color: white;
  position: relative;
}

.comparison-table thead::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--accent);
}

.comparison-table th {
  padding: 1.5rem 1.25rem;
  text-align: left;
  font-weight: 700;
  font-size: 1.125rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: none;
}

.comparison-table th:first-child {
  border-top-left-radius: var(--radius-lg);
}

.comparison-table th:last-child {
  border-top-right-radius: var(--radius-lg);
}

.comparison-table tbody tr {
  background: var(--glass-bg);
  border-bottom: 1px solid var(--glass-border);
  transition: var(--transition-base);
}

.comparison-table tbody tr:hover {
  background: var(--bg-card-hover);
  transform: scale(1.01);
  box-shadow: var(--shadow-md);
}

.comparison-table tbody tr:last-child {
  border-bottom: none;
}

.comparison-table tbody tr:last-child td:first-child {
  border-bottom-left-radius: var(--radius-lg);
}

.comparison-table tbody tr:last-child td:last-child {
  border-bottom-right-radius: var(--radius-lg);
}

.comparison-table td {
  padding: 1.5rem 1.25rem;
  color: var(--text-secondary);
  vertical-align: middle;
}

.comparison-table .feature-cell {
  font-weight: 700;
  color: var(--primary);
  font-size: 1.0625rem;
}

/* Rivers theme table fix */
.rivers-theme .styled-table .first-col {
  color: #48cae4;
  font-weight: 700;
}

/* ========================================
   FUN FACTS - VIBRANT GRID
======================================== */

.fun-facts-section {
  margin: 4rem 0;
  padding: 3rem;
  background: var(--gradient-hero);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-xl);
  position: relative;
  overflow: hidden;
}

.fun-facts-section::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
  animation: rotateBg 20s linear infinite;
}

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

.fun-facts-title {
  font-size: 2.5rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 3rem;
  color: white;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  position: relative;
  z-index: 1;
}

.fun-facts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  position: relative;
  z-index: 1;
}

.fun-fact {
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(10px);
  padding: 1.75rem;
  border-radius: var(--radius-lg);
  font-size: 1.0625rem;
  line-height: 1.7;
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.2);
  transition: var(--transition-base);
  cursor: default;
}

.fun-fact:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-5px) scale(1.02);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

/* ========================================
   MINDMAP SECTION - BRANCH SYSTEM
======================================== */

.mindmap-section {
  padding: var(--spacing-xl) 0;
}

.mindmap-intro {
  text-align: center;
  margin-bottom: 4rem;
}

.mindmap-branches {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.branch {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  overflow: hidden;
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-md);
  transition: var(--transition-slow);
  position: relative;
}

.branch::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 6px;
  height: 100%;
  background: var(--branch-color, var(--primary));
  transition: var(--transition-base);
}

.branch:hover {
  box-shadow: var(--shadow-xl);
  transform: translateY(-5px);
  border-color: var(--branch-color, var(--primary));
}

.branch:hover::before {
  width: 100%;
  opacity: 0.05;
}

.branch-header {
  padding: 2rem 2.5rem;
  background: linear-gradient(to right, rgba(0, 0, 0, 0.1), transparent);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: var(--transition-base);
  user-select: none;
}

.branch-header:hover {
  background: linear-gradient(to right, rgba(0, 0, 0, 0.15), transparent);
}

.branch-title-group {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.branch-icon {
  font-size: 3.5rem;
  filter: drop-shadow(0 0 20px var(--branch-color, var(--accent)));
  animation: iconFloat 3s ease-in-out infinite;
}

.branch-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.expand-btn {
  width: 3.5rem;
  height: 3.5rem;
  border-radius: 50%;
  background: var(--branch-color, var(--primary));
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 700;
  transition: var(--transition-bounce);
  flex-shrink: 0;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.expand-btn:hover {
  transform: scale(1.15) rotate(90deg);
  box-shadow: 0 8px 30px var(--branch-color, var(--primary-glow));
}

.expand-icon {
  display: block;
  transition: var(--transition-base);
}

.branch.expanded .expand-icon {
  transform: rotate(45deg);
}

.branch-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.branch.expanded .branch-content {
  max-height: 10000px;
  padding: 0 2.5rem 2.5rem;
}

.branch-definition {
  margin-bottom: 2.5rem;
  padding: 2rem;
  background: var(--gradient-card);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--branch-color, var(--primary));
}

.branch-definition h4 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--branch-color, var(--primary));
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.branch-definition p {
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--text-secondary);
}

/* Formation Process */
.formation-process {
  margin-bottom: 2.5rem;
  padding: 2.5rem;
  background: linear-gradient(135deg, rgba(0, 0, 0, 0.2), rgba(0, 0, 0, 0.05));
  border-radius: var(--radius-xl);
  border: 1px solid var(--glass-border);
}

.formation-process h4 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--branch-color, var(--primary));
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.formation-steps {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.formation-step {
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  padding: 1.75rem;
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--branch-color, var(--primary));
  box-shadow: var(--shadow-sm);
  transition: var(--transition-base);
  cursor: default;
}

.formation-step:hover {
  transform: translateX(10px);
  box-shadow: var(--shadow-md);
  background: var(--bg-card-hover);
}

.step-header {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-bottom: 1rem;
}

.step-icon {
  font-size: 2.5rem;
  filter: drop-shadow(0 0 10px var(--branch-color, var(--accent)));
}

.step-number {
  font-weight: 800;
  color: var(--branch-color, var(--primary));
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 0.5rem 1rem;
  background: var(--gradient-card);
  border-radius: var(--radius-full);
}

.step-text {
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.step-arrow {
  text-align: center;
  font-size: 2.5rem;
  color: var(--branch-color, var(--primary));
  opacity: 0.4;
  margin: 0.5rem 0;
  animation: arrowBounce 2s ease-in-out infinite;
}

@keyframes arrowBounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(5px); }
}

@keyframes arrowPulse {
  0%, 100% { transform: translateY(0); opacity: 0.5; }
  50% { transform: translateY(5px); opacity: 0.8; }
}

/* Characteristics */
.branch-characteristics {
  margin-bottom: 2.5rem;
}

.branch-characteristics h4 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--branch-color, var(--primary));
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.characteristics-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.characteristics-list li {
  padding: 1.25rem;
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--branch-color, var(--primary));
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--text-secondary);
  box-shadow: var(--shadow-sm);
  transition: var(--transition-base);
}

.characteristics-list li:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  background: var(--bg-card-hover);
  border-left-width: 5px;
}

/* Branch Examples */
.branch-examples {
  margin-bottom: 1.5rem;
}

.branch-examples h4 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--branch-color, var(--primary));
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.examples-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.example-card {
  position: relative;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: var(--transition-slow);
  display: block;
  border: 1px solid var(--glass-border);
}

.example-card:hover {
  transform: translateY(-12px) scale(1.02);
  box-shadow: var(--shadow-xl), 0 0 50px var(--primary-glow);
  border-color: var(--branch-color, var(--primary));
}

.example-image {
  width: 100%;
  height: 220px;
  background-size: cover;
  background-position: center;
  position: relative;
  overflow: hidden;
}

.example-card:hover .example-image {
  transform: scale(1.1);
  transition: var(--transition-slow);
}

.example-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom, transparent 0%, rgba(0, 0, 0, 0.7) 100%);
}

.example-info {
  padding: 2rem;
}

.example-name {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 1rem;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.example-location,
.example-detail,
.example-peak {
  font-size: 0.9375rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
  line-height: 1.6;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.example-location::before { content: '📍'; }
.example-detail::before { content: '⏳'; }
.example-peak::before { content: '🏔️'; }

.example-hover {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 1.5rem;
  background: var(--gradient-hero);
  color: white;
  text-align: center;
  font-weight: 700;
  font-size: 1.125rem;
  opacity: 0;
  transform: translateY(100%);
  transition: var(--transition-base);
}

.example-card:hover .example-hover {
  opacity: 1;
  transform: translateY(0);
}

.hover-text {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.hover-text::after {
  content: '→';
  font-size: 1.5rem;
  transition: var(--transition-base);
}

.example-card:hover .hover-text::after {
  transform: translateX(5px);
}

/* Comparison Table in Mindmap */
.comparison-table-section {
  margin-top: 4rem;
  padding: 3rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
}

.table-title {
  font-size: 2rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 2.5rem;
  background: var(--gradient-sunset);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.table-responsive {
  overflow-x: auto;
  border-radius: var(--radius-lg);
}

.styled-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 0.9375rem;
}

.styled-table thead {
  background: var(--gradient-hero);
  color: white;
}

.styled-table th {
  padding: 1.25rem 1rem;
  text-align: left;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: 0.875rem;
}

.styled-table th:first-child {
  border-top-left-radius: var(--radius-lg);
}

.styled-table th:last-child {
  border-top-right-radius: var(--radius-lg);
}

.styled-table tbody tr {
  background: var(--glass-bg);
  border-bottom: 1px solid var(--glass-border);
  transition: var(--transition-base);
}

.styled-table tbody tr:hover {
  background: var(--bg-card-hover);
  transform: scale(1.005);
}

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

.styled-table td {
  padding: 1.25rem 1rem;
  color: var(--text-secondary);
  vertical-align: middle;
}

.styled-table .first-col {
  font-weight: 700;
  color: var(--primary);
}

/* ========================================
   TIMELINE SECTION - STORY MODE
======================================== */

.timeline-section {
  padding: var(--spacing-xl) 0;
}

.timeline-viewer {
  position: relative;
  margin: 4rem 0;
}

.timeline-stage {
  display: none;
  opacity: 0;
}

.timeline-stage.active {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
  animation: stageFadeIn 0.8s ease-out forwards;
}

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

.stage-visual {
  position: sticky;
  top: 100px;
}

.stage-image-wrapper {
  position: relative;
  border-radius: var(--radius-2xl);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--glass-border);
}

.stage-image {
  width: 100%;
  height: 550px;
  object-fit: cover;
  display: block;
  transition: var(--transition-slow);
}

.stage-image-wrapper:hover .stage-image {
  transform: scale(1.05);
}

.stage-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom, transparent 40%, rgba(0, 0, 0, 0.5) 100%);
  pointer-events: none;
}

.stage-content {
  padding: 3rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
}

.stage-header {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--glass-border);
}

.stage-number {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--gradient-hero);
  color: white;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-glow);
}

.stage-title {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 1rem;
  line-height: 1.2;
}

.stage-timeframe {
  display: inline-block;
  padding: 0.75rem 1.25rem;
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 700;
  color: var(--accent);
}

.stage-description h4 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: var(--primary);
}

.stage-list {
  list-style: none;
  margin-bottom: 2.5rem;
}

.stage-list li {
  padding: 1rem 0;
  padding-left: 2.5rem;
  position: relative;
  line-height: 1.8;
  color: var(--text-secondary);
  border-left: 2px solid var(--glass-border);
  margin-left: 1rem;
  transition: var(--transition-base);
}

.stage-list li:hover {
  color: var(--text-primary);
  border-left-color: var(--primary);
}

.stage-list li::before {
  content: '→';
  position: absolute;
  left: -1.5rem;
  color: var(--primary);
  font-weight: 700;
  font-size: 1.25rem;
  background: var(--bg-card);
  padding: 0 0.5rem;
}

.geological-process {
  padding: 2rem;
  background: var(--gradient-card);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--accent);
  box-shadow: var(--shadow-sm);
}

.geological-process h4 {
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 1rem;
}

.geological-process p {
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

/* Timeline Controls */
.timeline-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  margin: 4rem 0;
}

.timeline-btn {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 2rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 2px solid var(--primary);
  color: var(--primary);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 1.0625rem;
  transition: var(--transition-base);
  cursor: pointer;
  box-shadow: var(--shadow-md);
}

.timeline-btn:hover:not(:disabled) {
  background: var(--gradient-hero);
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow);
  border-color: transparent;
}

.timeline-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
  border-color: var(--text-muted);
}

.stage-indicators {
  display: flex;
  gap: 1.5rem;
  padding: 1rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-full);
  border: 1px solid var(--glass-border);
}

.stage-dot {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 3px solid var(--glass-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.125rem;
  color: var(--text-muted);
  transition: var(--transition-bounce);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.stage-dot::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-hero);
  opacity: 0;
  transition: var(--transition-base);
}

.stage-dot:hover {
  transform: scale(1.15);
  border-color: var(--primary);
}

.stage-dot.active {
  background: var(--gradient-hero);
  border-color: var(--primary);
  color: white;
  transform: scale(1.2);
  box-shadow: var(--shadow-glow);
}

.stage-dot.active::before {
  opacity: 1;
}

.dot-label {
  position: relative;
  z-index: 1;
}

/* Terminology Section */
.terminology-section {
  margin: 4rem 0;
  padding: 4rem 3rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
}

.terminology-title {
  font-size: 2.5rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 4rem;
  background: var(--gradient-arctic);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.terms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 2.5rem;
}

.term-card {
  padding: 2.5rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-xl);
  border: 2px solid var(--glass-border);
  transition: var(--transition-slow);
  cursor: default;
}

.term-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-xl);
  transform: translateY(-8px) scale(1.02);
  background: var(--bg-card-hover);
}

.term-header {
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 2px solid var(--glass-border);
}

.term-name {
  font-size: 1.75rem;
  font-weight: 800;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.75rem;
}

.term-pronunciation {
  font-size: 1rem;
  color: var(--text-muted);
  font-style: italic;
  font-weight: 500;
}

.term-definition {
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.term-example {
  padding: 1.25rem;
  background: var(--gradient-card);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--accent);
  margin-bottom: 1.5rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.term-example strong {
  color: var(--primary);
  font-weight: 700;
}

.related-terms {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  font-size: 0.875rem;
}

.related-terms strong {
  width: 100%;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
  font-weight: 700;
}

.related-tag {
  padding: 0.5rem 1rem;
  background: var(--gradient-hero);
  color: white;
  border-radius: var(--radius-full);
  font-size: 0.8125rem;
  font-weight: 600;
  transition: var(--transition-base);
  cursor: default;
}

.related-tag:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-glow);
}

/* ========================================
   GRID SECTION (EXAMPLES) - MASONRY
======================================== */

.examples-section {
  padding: var(--spacing-xl) 0;
}

.examples-grid-featured {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
  margin-bottom: 4rem;
}

.range-card {
  position: relative;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  transition: var(--transition-slow);
  display: block;
  border: 1px solid var(--glass-border);
}

.range-card:hover {
  transform: translateY(-15px) scale(1.02);
  box-shadow: var(--shadow-xl), var(--shadow-neon);
  border-color: var(--primary);
}

.range-image {
  width: 100%;
  height: 200px;
  background-size: cover;
  background-position: center;
  position: relative;
  overflow: hidden;
}

.range-card:hover .range-image {
  animation: kenBurnsSmall 10s ease-in-out;
}

@keyframes kenBurnsSmall {
  0% { transform: scale(1); }
  100% { transform: scale(1.15); }
}

.range-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom, transparent 0%, rgba(0, 0, 0, 0.8) 100%);
}

.range-icon {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  font-size: 2.5rem;
  filter: drop-shadow(0 4px 20px rgba(0, 0, 0, 0.5));
  animation: iconFloat 3s ease-in-out infinite;
}

.range-info {
  padding: 1.25rem;
}

.range-name {
  font-size: 1.25rem !important;
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

.meta-item {
  font-size: 0.8rem !important;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.range-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1rem;
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 0.75rem;
  background: var(--gradient-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--glass-border);
}

.stat-label {
  font-size: 0.65rem !important;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
}

.stat-value {
  font-size: 0.85rem !important;
  font-weight: 800;
  color: var(--primary);
}

.fun-fact-badge {
  padding: 0.75rem;
  background: var(--gradient-sunset);
  color: white;
  border-radius: var(--radius-lg);
  font-size: 0.8rem !important;
  line-height: 1.4;
  font-weight: 600;
  box-shadow: var(--shadow-md);
}

.range-hover {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 1rem;
  background: var(--gradient-hero);
  color: white;
  text-align: center;
  font-weight: 800;
  font-size: 1rem;
  opacity: 0;
  transform: translateY(100%);
  transition: var(--transition-base);
}

.range-card:hover .range-hover {
  opacity: 1;
  transform: translateY(0);
}

/* View All Button */
.view-all-section {
  text-align: center;
  margin: 4rem 0;
}

.btn-view-all {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem 3rem;
  background: var(--gradient-hero);
  color: white;
  border-radius: var(--radius-full);
  font-weight: 800;
  font-size: 1.125rem;
  box-shadow: var(--shadow-lg);
  transition: var(--transition-bounce);
  border: 2px solid transparent;
}

.btn-view-all:hover {
  transform: translateY(-5px) scale(1.05);
  box-shadow: var(--shadow-neon);
  border-color: white;
}

/* UPSC Section */
.upsc-section {
  margin: 4rem 0;
  padding: 4rem 3rem;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(236, 72, 153, 0.05) 100%);
  border-radius: var(--radius-2xl);
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-xl);
  position: relative;
  overflow: hidden;
}

.upsc-section::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 200px;
  height: 200px;
  background: var(--gradient-glow);
  opacity: 0.3;
  border-radius: 50%;
  filter: blur(80px);
}

.upsc-header {
  text-align: center;
  margin-bottom: 4rem;
  position: relative;
  z-index: 1;
}

.upsc-badge {
  display: inline-block;
  padding: 0.75rem 2rem;
  background: var(--gradient-hero);
  color: white;
  border-radius: var(--radius-full);
  font-weight: 800;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-glow);
  animation: badgePulse 2s ease-in-out infinite;
}

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

.upsc-header h3 {
  font-size: 2.5rem;
  font-weight: 900;
  background: var(--gradient-sunset);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.upsc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2.5rem;
  position: relative;
  z-index: 1;
}

.upsc-box {
  padding: 2.5rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-md);
  transition: var(--transition-base);
}

.upsc-box:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}

.upsc-box h4 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

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

.upsc-list li {
  padding: 1.25rem 0;
  padding-left: 3rem;
  border-bottom: 1px solid var(--glass-border);
  position: relative;
  line-height: 1.8;
  color: var(--text-secondary);
  transition: var(--transition-base);
}

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

.upsc-list li:hover {
  color: var(--text-primary);
  padding-left: 3.5rem;
}

.upsc-list li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--primary);
  font-weight: 800;
  font-size: 1.5rem;
}

.upsc-list.questions li::before {
  content: '❓';
  font-size: 1.25rem;
}

/* ========================================
   SECTION NAVIGATION - STICKY
======================================== */

.concept-nav {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-top: 1px solid var(--glass-border);
  border-bottom: 1px solid var(--glass-border);
  padding: 1.5rem 0;
  position: sticky;
  top: 70px;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.concept-nav .nav-container {
  max-width: 1600px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
}

.concept-nav .nav-title {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-weight: 800;
  color: var(--text-primary);
  font-size: 1.125rem;
}

.concept-nav .nav-icon {
  font-size: 1.75rem;
  filter: drop-shadow(0 0 10px var(--primary-glow));
}

.concept-nav .nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  flex: 1;
}

.concept-nav .nav-link {
  padding: 0.75rem 1.5rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  color: var(--text-secondary);
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.9375rem;
  transition: var(--transition-base);
  white-space: nowrap;
  border: 1px solid var(--glass-border);
}

.concept-nav .nav-link:hover {
  background: var(--bg-card-hover);
  color: var(--primary);
  transform: translateY(-2px);
  border-color: var(--primary);
}

.concept-nav .nav-link.active {
  background: var(--gradient-hero);
  color: white;
  box-shadow: var(--shadow-glow);
  border-color: transparent;
}

/* ========================================
   HUB PAGE - TOPIC CARDS
======================================== */

/* Intro section */
.intro-section {
  padding: 4rem 0;
  background: var(--bg-dark);
}

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

.intro-card {
  text-align: center;
  padding: 2rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  transition: var(--transition-smooth);
}

.intro-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}

.intro-icon {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  filter: drop-shadow(0 0 20px var(--primary-glow));
}

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

.intro-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Topics main */
.topics-main {
  padding: 6rem 0;
}

/* Section header */
.section-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-badge {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--primary);
  margin-bottom: 1.5rem;
}

.section-title {
  font-size: 3rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 700px;
  margin: 0 auto;
}

/* Topics grid */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
  gap: 2.5rem;
}

/* Topic card */
.topic-card {
  position: relative;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  transition: var(--transition-slow);
  display: block;
  text-decoration: none;
  border: 1px solid var(--glass-border);
}

.topic-card:hover {
  transform: translateY(-15px) scale(1.02);
  box-shadow: var(--shadow-xl), var(--shadow-neon);
  border-color: var(--primary);
}

.topic-image {
  position: relative;
  width: 100%;
  height: 220px;
  overflow: hidden;
}

.topic-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition-slow);
}

.topic-card:hover .topic-image img {
  transform: scale(1.1);
}

.topic-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 0%, rgba(0, 0, 0, 0.8) 100%);
}

.topic-icon {
  position: absolute;
  top: 1rem;
  right: 1rem;
  font-size: 3rem;
  filter: drop-shadow(0 4px 20px rgba(0, 0, 0, 0.7));
  z-index: 2;
}

.topic-content {
  padding: 2rem;
}

.topic-title {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.topic-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.topic-sections {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.section-tag {
  padding: 0.5rem 1rem;
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: var(--transition-base);
}

.topic-card:hover .section-tag {
  background: var(--primary);
  color: white;
  border-color: transparent;
}

.topic-arrow {
  position: absolute;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background: var(--gradient-hero);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: white;
  opacity: 0;
  transform: translateX(-10px);
  transition: var(--transition-base);
}

.topic-card:hover .topic-arrow {
  opacity: 1;
  transform: translateX(0);
}

/* Quick concepts section */
.quick-concepts-section {
  padding: 6rem 0;
  background: var(--bg-dark);
}

.concepts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2.5rem;
}

.concept-card {
  padding: 2.5rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-2xl);
  transition: var(--transition-smooth);
}

.concept-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}

.concept-icon {
  font-size: 3.5rem;
  margin-bottom: 1.5rem;
  filter: drop-shadow(0 0 20px var(--primary-glow));
}

.concept-card h3 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
}

.concept-points {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 2rem;
}

.concept-points p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.concept-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--primary);
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
  transition: var(--transition-base);
}

.concept-link:hover {
  gap: 1rem;
}

/* Explore features section */
.explore-features-section {
  padding: 6rem 0;
}

.features-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.feature-link-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 2rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  text-decoration: none;
  transition: var(--transition-smooth);
}

.feature-link-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}

.feature-emoji {
  font-size: 3rem;
  filter: drop-shadow(0 0 15px var(--primary-glow));
}

.feature-name {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
}

.feature-count {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* ========================================
   FOOTER - MODERN
======================================== */

.main-footer {
  background: var(--bg-darkest);
  color: var(--text-secondary);
  padding: 4rem 0 2rem;
  margin-top: 6rem;
  border-top: 1px solid var(--glass-border);
}

.footer-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-section h4 {
  color: var(--text-primary);
  font-size: 1.25rem;
  margin-bottom: 1.5rem;
  font-weight: 800;
}

.footer-description {
  color: var(--text-muted);
  line-height: 1.8;
}

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

.footer-links li {
  margin-bottom: 1rem;
}

.footer-links a {
  color: var(--text-secondary);
  transition: var(--transition-base);
  display: inline-block;
}

.footer-links a:hover {
  color: var(--primary);
  transform: translateX(5px);
}

.footer-bottom {
  border-top: 1px solid var(--glass-border);
  padding-top: 2rem;
  margin-top: 3rem;
}

.footer-bottom .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.copyright {
  color: var(--text-muted);
  font-size: 0.9375rem;
}

.footer-social {
  display: flex;
  gap: 1.25rem;
}

.footer-social a {
  width: 45px;
  height: 45px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: 50%;
  color: var(--text-primary);
  transition: var(--transition-bounce);
}

.footer-social a:hover {
  background: var(--gradient-hero);
  border-color: transparent;
  transform: translateY(-5px) rotate(360deg);
  box-shadow: var(--shadow-glow);
}

/* Footer grid for hub */
.footer-top {
  padding: 4rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 3rem;
}

.footer-brand {
  max-width: 350px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  text-decoration: none;
}

.footer-tagline {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ========================================
   BACK TO TOP BUTTON - FLOATING
======================================== */

.back-to-top {
  position: fixed;
  bottom: 2.5rem;
  right: 2.5rem;
  width: 60px;
  height: 60px;
  background: var(--gradient-hero);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-xl);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px) scale(0.8);
  transition: var(--transition-bounce);
  z-index: 999;
  cursor: pointer;
  border: 2px solid white;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.back-to-top:hover {
  transform: translateY(-8px) scale(1.1) rotate(360deg);
  box-shadow: var(--shadow-neon);
}

.back-to-top svg {
  width: 24px;
  height: 24px;
}

/* ========================================
   404 ERROR PAGE
======================================== */

.error-404 {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--sky-day);
  text-align: center;
  padding: var(--spacing-xl);
}

.error-content {
  max-width: 500px;
}

.error-title {
  font-family: var(--font-display);
  font-size: 8rem;
  font-weight: 800;
  color: var(--ice-light);
  text-shadow: 0 0 50px rgba(100, 180, 255, 0.5);
  margin-bottom: var(--spacing-md);
  line-height: 1;
}

.error-message {
  font-size: 1.5rem;
  color: var(--text-light);
  margin-bottom: var(--spacing-sm);
}

.error-detail {
  color: var(--text-muted);
  margin-bottom: var(--spacing-xl);
  line-height: 1.8;
}

.btn-back {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  background: linear-gradient(135deg, var(--ice-dark), var(--glacier-blue));
  color: var(--text-light);
  border-radius: var(--radius-xl);
  font-weight: 600;
  text-decoration: none;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-medium);
}

.btn-back:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-strong), var(--shadow-ice);
}

/* ========================================
   ALL THEME DEFINITIONS - COMPLETE
======================================== */

/* VOLCANOES THEME - Fire/Orange */
.volcanoes-theme {
  --primary: #ff6b35;
  --primary-dark: #d4461f;
  --primary-light: #ff8c61;
  --primary-glow: rgba(255, 107, 53, 0.5);
  --accent: #ff9800;
  --accent-warm: #ff6b35;
  --accent-cool: #f4511e;
  --branch-color: #ff6b35;
  
  --bg-dark: #1a0a00;
  --bg-darker: #0d0500;
  --bg-darkest: #000000;
  --bg-card: rgba(255, 107, 53, 0.12);
  --bg-card-hover: rgba(255, 107, 53, 0.22);
  
  --glass-bg: rgba(255, 107, 53, 0.08);
  --glass-border: rgba(255, 140, 97, 0.25);
  --glass-shadow: rgba(212, 70, 31, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #ffd4c4;
  --text-muted: #ff8c61;
  
  --gradient-hero: linear-gradient(135deg, #ff6b35 0%, #ff9800 50%, #ffc107 100%);
  --gradient-card: linear-gradient(135deg, rgba(255, 107, 53, 0.15) 0%, rgba(255, 152, 0, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(255, 107, 53, 0.4);
  --shadow-neon: 0 0 20px rgba(255, 107, 53, 0.5), 0 0 40px rgba(255, 152, 0, 0.3);
}

.volcanoes-theme.concept-page {
  background: linear-gradient(180deg, #1a0a00 0%, #2d1000 50%, #451800 100%);
}

/* RIVERS THEME - Water Blue */
.rivers-theme {
  --primary: #0077b6;
  --primary-dark: #023e8a;
  --primary-light: #00b4d8;
  --primary-glow: rgba(0, 119, 182, 0.5);
  --accent: #48cae4;
  --accent-warm: #90e0ef;
  --accent-cool: #0096c7;
  --branch-color: #00b4d8;
  
  --bg-dark: #03045e;
  --bg-darker: #020240;
  --bg-darkest: #010124;
  --bg-card: rgba(0, 119, 182, 0.15);
  --bg-card-hover: rgba(0, 180, 216, 0.22);
  
  --glass-bg: rgba(0, 180, 216, 0.08);
  --glass-border: rgba(72, 202, 228, 0.25);
  --glass-shadow: rgba(2, 62, 138, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #caf0f8;
  --text-muted: #90e0ef;
  
  --gradient-hero: linear-gradient(135deg, #0077b6 0%, #00b4d8 50%, #48cae4 100%);
  --gradient-card: linear-gradient(135deg, rgba(0, 119, 182, 0.15) 0%, rgba(72, 202, 228, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(0, 180, 216, 0.4);
  --shadow-neon: 0 0 20px rgba(72, 202, 228, 0.5), 0 0 40px rgba(0, 180, 216, 0.3);
}

.rivers-theme.concept-page {
  background: linear-gradient(180deg, #03045e 0%, #023e8a 50%, #0077b6 100%);
}

/* WATERFALLS THEME - Cyan/Teal */
.waterfalls-theme {
  --primary: #00bcd4;
  --primary-dark: #008ba3;
  --primary-light: #33c9dc;
  --primary-glow: rgba(0, 188, 212, 0.5);
  --accent: #4dd0e1;
  --accent-warm: #80deea;
  --accent-cool: #00acc1;
  --branch-color: #00bcd4;
  
  --bg-dark: #004d5a;
  --bg-darker: #00363f;
  --bg-darkest: #001f24;
  --bg-card: rgba(0, 188, 212, 0.12);
  --bg-card-hover: rgba(0, 188, 212, 0.22);
  
  --glass-bg: rgba(0, 188, 212, 0.08);
  --glass-border: rgba(77, 208, 225, 0.25);
  --glass-shadow: rgba(0, 139, 163, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #b2ebf2;
  --text-muted: #80deea;
  
  --gradient-hero: linear-gradient(135deg, #00bcd4 0%, #4dd0e1 50%, #80deea 100%);
  --gradient-card: linear-gradient(135deg, rgba(0, 188, 212, 0.15) 0%, rgba(77, 208, 225, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(0, 188, 212, 0.4);
  --shadow-neon: 0 0 20px rgba(77, 208, 225, 0.5), 0 0 40px rgba(0, 188, 212, 0.3);
}

.waterfalls-theme.concept-page {
  background: linear-gradient(180deg, #004d5a 0%, #006978 50%, #00838f 100%);
}

/* DESERTS THEME - Sand/Orange */
.deserts-theme {
  --primary: #f4a261;
  --primary-dark: #e07a3a;
  --primary-light: #f6b686;
  --primary-glow: rgba(244, 162, 97, 0.5);
  --accent: #e9c46a;
  --accent-warm: #f4a261;
  --accent-cool: #e76f51;
  --branch-color: #f4a261;
  
  --bg-dark: #3d2314;
  --bg-darker: #2a180e;
  --bg-darkest: #170d08;
  --bg-card: rgba(244, 162, 97, 0.12);
  --bg-card-hover: rgba(244, 162, 97, 0.22);
  
  --glass-bg: rgba(244, 162, 97, 0.08);
  --glass-border: rgba(246, 182, 134, 0.25);
  --glass-shadow: rgba(224, 122, 58, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #fde8d7;
  --text-muted: #f6b686;
  
  --gradient-hero: linear-gradient(135deg, #e76f51 0%, #f4a261 50%, #e9c46a 100%);
  --gradient-card: linear-gradient(135deg, rgba(244, 162, 97, 0.15) 0%, rgba(233, 196, 106, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(244, 162, 97, 0.4);
  --shadow-neon: 0 0 20px rgba(244, 162, 97, 0.5), 0 0 40px rgba(233, 196, 106, 0.3);
}

.deserts-theme.concept-page {
  background: linear-gradient(180deg, #3d2314 0%, #5a3520 50%, #7a4a2a 100%);
}

/* LAKES THEME - Deep Blue */
.lakes-theme {
  --primary: #0077b6;
  --primary-dark: #005280;
  --primary-light: #3398c7;
  --primary-glow: rgba(0, 119, 182, 0.5);
  --accent: #00b4d8;
  --accent-warm: #48cae4;
  --accent-cool: #0096c7;
  --branch-color: #0077b6;
  
  --bg-dark: #002233;
  --bg-darker: #001522;
  --bg-darkest: #000a11;
  --bg-card: rgba(0, 119, 182, 0.12);
  --bg-card-hover: rgba(0, 119, 182, 0.22);
  
  --glass-bg: rgba(0, 119, 182, 0.08);
  --glass-border: rgba(51, 152, 199, 0.25);
  --glass-shadow: rgba(0, 82, 128, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #b8e0f0;
  --text-muted: #7dcde8;
  
  --gradient-hero: linear-gradient(135deg, #0077b6 0%, #00b4d8 50%, #48cae4 100%);
  --gradient-card: linear-gradient(135deg, rgba(0, 119, 182, 0.15) 0%, rgba(0, 180, 216, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(0, 119, 182, 0.4);
  --shadow-neon: 0 0 20px rgba(51, 152, 199, 0.5), 0 0 40px rgba(0, 180, 216, 0.3);
}

.lakes-theme.concept-page {
  background: linear-gradient(180deg, #002233 0%, #003855 50%, #005077 100%);
}

/* ISLANDS THEME - Tropical Green */
.islands-theme {
  --primary: #06d6a0;
  --primary-dark: #04a777;
  --primary-light: #38ddb3;
  --primary-glow: rgba(6, 214, 160, 0.5);
  --accent: #00c896;
  --accent-warm: #06d6a0;
  --accent-cool: #00b894;
  --branch-color: #06d6a0;
  
  --bg-dark: #003d32;
  --bg-darker: #002822;
  --bg-darkest: #001511;
  --bg-card: rgba(6, 214, 160, 0.12);
  --bg-card-hover: rgba(6, 214, 160, 0.22);
  
  --glass-bg: rgba(6, 214, 160, 0.08);
  --glass-border: rgba(56, 221, 179, 0.25);
  --glass-shadow: rgba(4, 167, 119, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #b8f5e5;
  --text-muted: #7aecd4;
  
  --gradient-hero: linear-gradient(135deg, #00b894 0%, #06d6a0 50%, #55efc4 100%);
  --gradient-card: linear-gradient(135deg, rgba(6, 214, 160, 0.15) 0%, rgba(85, 239, 196, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(6, 214, 160, 0.4);
  --shadow-neon: 0 0 20px rgba(56, 221, 179, 0.5), 0 0 40px rgba(6, 214, 160, 0.3);
}

.islands-theme.concept-page {
  background: linear-gradient(180deg, #003d32 0%, #005a48 50%, #00785f 100%);
}

/* CORAL REEFS THEME - Pink/Coral */
.coral-reefs-theme {
  --primary: #ff6392;
  --primary-dark: #d43d6a;
  --primary-light: #ff87a8;
  --primary-glow: rgba(255, 99, 146, 0.5);
  --accent: #ff85a2;
  --accent-warm: #ff6392;
  --accent-cool: #f472b6;
  --branch-color: #ff6392;
  
  --bg-dark: #3d1a28;
  --bg-darker: #2a111b;
  --bg-darkest: #17090e;
  --bg-card: rgba(255, 99, 146, 0.12);
  --bg-card-hover: rgba(255, 99, 146, 0.22);
  
  --glass-bg: rgba(255, 99, 146, 0.08);
  --glass-border: rgba(255, 135, 168, 0.25);
  --glass-shadow: rgba(212, 61, 106, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #ffd4e2;
  --text-muted: #ff87a8;
  
  --gradient-hero: linear-gradient(135deg, #ff6392 0%, #ff85a2 50%, #ffa8c0 100%);
  --gradient-card: linear-gradient(135deg, rgba(255, 99, 146, 0.15) 0%, rgba(255, 133, 162, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(255, 99, 146, 0.4);
  --shadow-neon: 0 0 20px rgba(255, 135, 168, 0.5), 0 0 40px rgba(255, 99, 146, 0.3);
}

.coral-reefs-theme.concept-page {
  background: linear-gradient(180deg, #3d1a28 0%, #5a2740 50%, #78355a 100%);
}

/* OCEANS THEME - Deep Ocean Blue */
.oceans-theme {
  --primary: #0466c8;
  --primary-dark: #02448a;
  --primary-light: #3684d3;
  --primary-glow: rgba(4, 102, 200, 0.5);
  --accent: #0077b6;
  --accent-warm: #00b4d8;
  --accent-cool: #023e8a;
  --branch-color: #0466c8;
  
  --bg-dark: #001d3d;
  --bg-darker: #001229;
  --bg-darkest: #000814;
  --bg-card: rgba(4, 102, 200, 0.12);
  --bg-card-hover: rgba(4, 102, 200, 0.22);
  
  --glass-bg: rgba(4, 102, 200, 0.08);
  --glass-border: rgba(54, 132, 211, 0.25);
  --glass-shadow: rgba(2, 68, 138, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #b8d4f0;
  --text-muted: #7db8e8;
  
  --gradient-hero: linear-gradient(135deg, #023e8a 0%, #0466c8 50%, #0077b6 100%);
  --gradient-card: linear-gradient(135deg, rgba(4, 102, 200, 0.15) 0%, rgba(0, 119, 182, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(4, 102, 200, 0.4);
  --shadow-neon: 0 0 20px rgba(54, 132, 211, 0.5), 0 0 40px rgba(0, 119, 182, 0.3);
}

.oceans-theme.concept-page {
  background: linear-gradient(180deg, #001d3d 0%, #002855 50%, #003566 100%);
}

/* FORESTS THEME - Green */
.forests-theme {
  --primary: #10b981;
  --primary-dark: #059669;
  --primary-light: #34d399;
  --primary-glow: rgba(16, 185, 129, 0.5);
  --accent: #22c55e;
  --accent-warm: #34d399;
  --accent-cool: #14b8a6;
  --branch-color: #10b981;
  
  --bg-dark: #052e16;
  --bg-darker: #031d0f;
  --bg-darkest: #010d07;
  --bg-card: rgba(16, 185, 129, 0.12);
  --bg-card-hover: rgba(16, 185, 129, 0.22);
  
  --glass-bg: rgba(16, 185, 129, 0.08);
  --glass-border: rgba(52, 211, 153, 0.25);
  --glass-shadow: rgba(5, 150, 105, 0.4);
  
  --text-primary: #ffffff;
  --text-secondary: #d1fae5;
  --text-muted: #6ee7b7;
  
  --gradient-hero: linear-gradient(135deg, #059669 0%, #10b981 50%, #34d399 100%);
  --gradient-card: linear-gradient(135deg, rgba(16, 185, 129, 0.15) 0%, rgba(34, 197, 94, 0.08) 100%);
  
  --shadow-glow: 0 0 40px rgba(16, 185, 129, 0.4);
  --shadow-neon: 0 0 20px rgba(52, 211, 153, 0.5), 0 0 40px rgba(16, 185, 129, 0.3);
}

.forests-theme.concept-page {
  background: linear-gradient(180deg, #052e16 0%, #064e3b 50%, #065f46 100%);
}

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

@media (max-width: 1024px) {
  .timeline-stage.active {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .stage-visual {
    position: static;
  }
  
  .stage-image {
    height: 400px;
  }
  
  .examples-grid-featured {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  }
  
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  /* Navigation */
  .mobile-menu-toggle {
    display: flex;
  }
  
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--bg-darker);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    border-bottom: 1px solid var(--glass-border);
  }
  
  .nav-links.active {
    max-height: 600px;
  }
  
  .nav-link {
    width: 100%;
    justify-content: center;
    padding: 1rem 1.5rem;
  }
  
  /* Hero */
  .concept-hero {
    height: 70vh;
    min-height: 500px;
  }
  
  .hero-title {
    font-size: 2.5rem;
  }
  
  .hero-tagline {
    font-size: 1.125rem;
  }
  
  /* Content */
  .key-points-grid,
  .examples-grid,
  .examples-grid-featured,
  .topics-grid,
  .concepts-grid {
    grid-template-columns: 1fr;
  }
  
  .timeline-controls {
    flex-direction: column;
    gap: 2rem;
  }
  
  .stage-indicators {
    order: -1;
  }
  
  .concept-nav {
    position: static;
  }
  
  .concept-nav .nav-container {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .concept-nav .nav-links {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 1rem;
  }
  
  .footer-content,
  .footer-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-bottom .container {
    flex-direction: column;
    text-align: center;
  }
  
  .features-links {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .hero-stats {
    gap: 2rem;
  }
  
  .stat-value {
    font-size: 2.5rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 1.25rem;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .comparison-section,
  .terminology-section,
  .upsc-section {
    padding: 2rem 1.5rem;
  }
  
  .branch-content {
    padding: 0 1.5rem 1.5rem;
  }
  
  .stage-image {
    height: 300px;
  }
  
  .stage-content {
    padding: 2rem 1.5rem;
  }
  
  .back-to-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 50px;
    height: 50px;
  }
  
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  h3 { font-size: 1.25rem; }
  
  .section-title {
    font-size: 2rem;
  }
  
  .topic-title {
    font-size: 1.5rem;
  }
  
  .features-links {
    grid-template-columns: 1fr;
  }
}

/* ========================================
   PRINT STYLES
======================================== */

@media print {
  .main-nav,
  .concept-nav,
  .main-footer,
  .back-to-top,
  .preloader,
  .timeline-controls,
  .expand-btn {
    display: none !important;
  }
  
  .concept-hero {
    height: auto;
    min-height: auto;
    page-break-after: always;
  }
  
  .branch {
    page-break-inside: avoid;
  }
  
  .branch-content {
    max-height: none !important;
    padding: 1.5rem !important;
  }
  
  .timeline-stage {
    display: block !important;
    page-break-inside: avoid;
  }
  
  body {
    font-size: 12pt;
    background: white;
    color: black;
  }
}

/* ========================================
   ACCESSIBILITY
======================================== */

*:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media (prefers-contrast: high) {
  .comparison-table,
  .term-card,
  .example-card,
  .range-card {
    border: 3px solid currentColor;
  }
}

/* ========================================
   SCROLL ANIMATIONS (Added via JS)
======================================== */

[data-aos] {
  opacity: 0;
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-aos].aos-animate {
  opacity: 1;
}

[data-aos="fade-up"] {
  transform: translateY(30px);
}

[data-aos="fade-up"].aos-animate {
  transform: translateY(0);
}

[data-aos="fade-in"] {
  transform: scale(0.95);
}

[data-aos="fade-in"].aos-animate {
  transform: scale(1);
}
/* ============================================
   BRANCH SYSTEM - CLEAN VERSION
   ============================================ */

.branch {
  background: var(--bg-card, rgba(30, 41, 59, 0.8));
  border-radius: 16px;
  margin-bottom: 1.5rem;
  border: 1px solid var(--glass-border, rgba(255,255,255,0.1));
  border-left: 5px solid var(--branch-color, #6366f1);
  overflow: hidden;
}

.branch-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  background: rgba(0,0,0,0.1);
}

.branch-header:hover {
  background: rgba(0,0,0,0.2);
}

.branch-title-group {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.branch-icon {
  font-size: 2rem;
}

.branch-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary, #f1f5f9);
  margin: 0;
}

.expand-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--branch-color, #6366f1);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: bold;
  flex-shrink: 0;
}

.expand-icon {
  line-height: 1;
}

/* Content - HIDDEN by default */
.branch-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
}

.branch-inner {
  padding: 1.5rem;
  border-top: 1px solid var(--glass-border, rgba(255,255,255,0.1));
}

/* Definition */
.branch-definition {
  margin-bottom: 1.5rem;
  padding: 1.25rem;
  background: rgba(99, 102, 241, 0.1);
  border-radius: 12px;
  border-left: 4px solid var(--branch-color, #6366f1);
}

.branch-definition h4 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--branch-color, #6366f1);
  margin: 0 0 0.75rem 0;
}

.branch-definition p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-secondary, #94a3b8);
  margin: 0;
}

/* Formation Process */
.formation-process {
  margin-bottom: 1.5rem;
  padding: 1.5rem;
  background: rgba(0,0,0,0.15);
  border-radius: 12px;
}

.formation-process h4 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--branch-color, #6366f1);
  margin: 0 0 1rem 0;
}

.formation-steps {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.formation-step {
  padding: 1rem;
  background: var(--bg-card, rgba(30, 41, 59, 0.8));
  border-radius: 10px;
  border-left: 3px solid var(--branch-color, #6366f1);
}

.step-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.step-icon {
  font-size: 1.25rem;
}

.step-number {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--branch-color, #6366f1);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: rgba(99, 102, 241, 0.15);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
}

.step-text {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text-secondary, #94a3b8);
  margin: 0;
}

/* Characteristics */
.branch-characteristics {
  margin-bottom: 1rem;
}

.branch-characteristics h4 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--branch-color, #6366f1);
  margin: 0 0 1rem 0;
}

.characteristics-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 0.5rem;
}

.characteristics-list li {
  padding: 0.875rem 1rem;
  background: var(--bg-card, rgba(30, 41, 59, 0.8));
  border-radius: 8px;
  border-left: 3px solid var(--branch-color, #6366f1);
  font-size: 0.9rem;
  line-height: 1.5;
  color: var(--text-secondary, #94a3b8);
}

/* Mobile */
@media (max-width: 768px) {
  .branch-header {
    padding: 1rem;
  }
  
  .branch-title {
    font-size: 1rem;
  }
  
  .branch-icon {
    font-size: 1.5rem;
  }
  
  .expand-btn {
    width: 36px;
    height: 36px;
    font-size: 1.25rem;
  }
  
  .branch-inner {
    padding: 1rem;
  }
  
  .characteristics-list {
    grid-template-columns: 1fr;
  }
}
/* ============================================
   EXPLORE CTA - Single Button Section
   ============================================ */

.explore-cta {
  display: flex;
  justify-content: center;
  padding: 4rem 0;
}

.cta-content {
  text-align: center;
  max-width: 600px;
  padding: 4rem 3rem;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
}

.cta-icon {
  font-size: 5rem;
  margin-bottom: 1.5rem;
  filter: drop-shadow(0 0 30px var(--primary-glow));
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.cta-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 1rem;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.cta-description {
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.cta-button {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem 3rem;
  background: var(--gradient-hero);
  color: white;
  border-radius: var(--radius-full);
  font-weight: 800;
  font-size: 1.25rem;
  text-decoration: none;
  box-shadow: var(--shadow-lg);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.cta-button:hover {
  transform: translateY(-5px) scale(1.05);
  box-shadow: var(--shadow-glow), var(--shadow-xl);
}

.cta-button svg {
  transition: transform 0.3s ease;
}

.cta-button:hover svg {
  transform: translateX(5px);
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .cta-content {
    padding: 3rem 2rem;
    margin: 0 1rem;
  }
  
  .cta-icon {
    font-size: 4rem;
  }
  
  .cta-title {
    font-size: 1.75rem;
  }
  
  .cta-description {
    font-size: 1rem;
  }
  
  .cta-button {
    padding: 1rem 2rem;
    font-size: 1rem;
  }
}
/* ============================================
   MOBILE FIXES - MINIMAL VERSION
   ============================================ */

@media (max-width: 768px) {
  
  /* Hero title fix */
  .hero-title {
    font-size: 1.75rem !important;
    flex-direction: column !important;
    gap: 0.5rem !important;
  }
  
  /* Branch header fix - clickable area */
  .branch-header {
    padding: 1rem !important;
  }
  
  .branch-title {
    font-size: 1rem !important;
    word-break: break-word !important;
  }
  
  .branch-icon {
    font-size: 1.75rem !important;
  }
  
  .expand-btn {
    width: 36px !important;
    height: 36px !important;
    min-width: 36px !important;
    flex-shrink: 0 !important;
  }
  
  /* CTA Button fix */
  .cta-content {
    padding: 2rem 1.5rem !important;
    margin: 0 1rem !important;
  }
  
  .cta-title {
    font-size: 1.5rem !important;
  }
  
  .cta-button {
    width: 100% !important;
    justify-content: center !important;
    padding: 1rem 1.5rem !important;
    font-size: 1rem !important;
  }
  
  /* Container padding */
  .container {
    padding-left: 1rem !important;
    padding-right: 1rem !important;
  }
}

@media (max-width: 480px) {
  
  .hero-title {
    font-size: 1.5rem !important;
  }
  
  .branch-title {
    font-size: 0.95rem !important;
  }
  
  .cta-title {
    font-size: 1.25rem !important;
  }
}
/* === MOBILE FIX - ADD AT END === */
@media (max-width: 768px) {
  .hero-title { font-size: 1.5rem !important; }
  .branch-title { font-size: 1rem !important; }
  .cta-button { width: 90% !important; font-size: 0.9rem !important; }
  .cta-title { font-size: 1.3rem !important; }
  .cta-content { margin: 0 1rem !important; padding: 1.5rem !important; }
  .container { padding: 0 1rem !important; }
}
/* ============================================
   FIX: TOPIC SECTIONS VISIBILITY ON MOBILE
   (Coral Reefs Topics, etc.)
   ============================================ */

.topic-sections {
  display: flex !important;
  flex-wrap: wrap !important;
  gap: 0.5rem !important;
  overflow: visible !important;
}

.section-tag {
  display: inline-block !important;
  white-space: nowrap !important;
  font-size: 0.7rem !important;
  padding: 0.4rem 0.8rem !important;
}

/* Mobile specific fix for topic cards */
@media (max-width: 768px) {
  .topic-content {
    padding: 1.25rem !important;
    overflow: visible !important;
  }
  
  .topic-sections {
    display: flex !important;
    flex-wrap: wrap !important;
    gap: 0.4rem !important;
    max-height: none !important;
    overflow: visible !important;
  }
  
  .section-tag {
    font-size: 0.65rem !important;
    padding: 0.3rem 0.6rem !important;
  }
  
  .topic-card {
    overflow: visible !important;
    min-height: auto !important;
  }
  
  .topic-title {
    font-size: 1.25rem !important;
  }
  
  .topic-desc {
    font-size: 0.85rem !important;
    margin-bottom: 1rem !important;
  }
}

@media (max-width: 480px) {
  .section-tag {
    font-size: 0.6rem !important;
    padding: 0.25rem 0.5rem !important;
  }
  
  .topic-sections {
    gap: 0.3rem !important;
  }
/* END OF STYLE.CSS */