/* ==========================================================================
   SPEED MATH: MENTAL MATH QUIZ - DESIGN SYSTEM & STYLESHEET
   A modern, high-performance landing page design system
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@500;700&family=Plus+Jakarta+Sans:wght@400;500;600;700;800&display=swap');

:root {
  /* Core Color Palette - Dark Obsidian (Default) */
  --bg-primary: #07090e;
  --bg-secondary: #0d121f;
  --bg-tertiary: #131b2e;
  --bg-card: rgba(19, 27, 46, 0.7);
  --bg-card-hover: rgba(27, 38, 65, 0.85);
  --bg-glass: rgba(13, 18, 31, 0.75);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-inverse: #07090e;

  --accent-cyan: #06b6d4;
  --accent-emerald: #10b981;
  --accent-indigo: #6366f1;
  --accent-purple: #8b5cf6;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;

  --gradient-brand: linear-gradient(135deg, #06b6d4 0%, #6366f1 50%, #a855f7 100%);
  --gradient-accent: linear-gradient(135deg, #10b981 0%, #06b6d4 100%);
  --gradient-hero-glow: radial-gradient(circle at 50% 20%, rgba(99, 102, 241, 0.22) 0%, rgba(6, 182, 212, 0.12) 35%, transparent 70%);
  --gradient-card-border: linear-gradient(135deg, rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0.02));

  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(6, 182, 212, 0.45);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 20px 45px -15px rgba(0, 0, 0, 0.7);
  --shadow-glow: 0 0 30px -5px rgba(99, 102, 241, 0.35);
  --shadow-emerald: 0 0 30px -5px rgba(16, 185, 129, 0.35);

  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;

  --transition-fast: 0.18s ease;
  --transition-normal: 0.28s ease;
  --transition-slow: 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Light Theme overrides */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(255, 255, 255, 1);
  --bg-glass: rgba(255, 255, 255, 0.82);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-inverse: #f8fafc;

  --gradient-hero-glow: radial-gradient(circle at 50% 20%, rgba(99, 102, 241, 0.12) 0%, rgba(6, 182, 212, 0.08) 35%, transparent 70%);
  --gradient-card-border: linear-gradient(135deg, rgba(0, 0, 0, 0.08), rgba(0, 0, 0, 0.02));

  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-focus: rgba(99, 102, 241, 0.5);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 10px 30px -10px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 45px -15px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 30px -5px rgba(99, 102, 241, 0.2);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  color-scheme: dark light;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  background-image: 
    radial-gradient(at 10% 15%, rgba(99, 102, 241, 0.12) 0px, transparent 45%),
    radial-gradient(at 90% 60%, rgba(6, 182, 212, 0.1) 0px, transparent 40%),
    radial-gradient(at 50% 90%, rgba(16, 185, 129, 0.08) 0px, transparent 40%);
  background-attachment: fixed;
}

/* Layout Container */
.container {
  width: 100%;
  max-width: 1220px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography Utilities */
h1, h2, h3, h4, h5 {
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.025em;
  color: var(--text-primary);
}

.text-gradient {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
}

.text-emerald {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.mono {
  font-family: var(--font-mono);
}

/* ==========================================================================
   NAVIGATION BAR
   ========================================================================== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  background: var(--bg-glass);
  border-bottom: 1px solid var(--border-subtle);
  transition: all var(--transition-normal);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 74px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
}

.brand-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
  object-fit: cover;
  transition: transform var(--transition-fast);
}

.brand-icon:hover {
  transform: scale(1.05) rotate(2deg);
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.22rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.brand-tag {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-link {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition-fast);
  position: relative;
}

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-brand);
  border-radius: var(--radius-full);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* Theme Toggle Button */
.theme-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  width: 42px;
  height: 42px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.theme-btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.theme-btn svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Base Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 24px;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--gradient-brand);
  color: #ffffff;
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 25px -4px rgba(99, 102, 241, 0.5);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-focus);
  transform: translateY(-2px);
}

.btn-emerald {
  background: var(--gradient-accent);
  color: #07090e;
  font-weight: 700;
  box-shadow: var(--shadow-emerald);
}

.btn-emerald:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 25px -4px rgba(16, 185, 129, 0.5);
}

/* Play Store Badge Button */
.btn-playstore {
  background: #000000;
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.22);
  padding: 10px 20px;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-md);
}

[data-theme="light"] .btn-playstore {
  background: #0f172a;
}

.btn-playstore:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 28px -5px rgba(0, 0, 0, 0.5);
  border-color: var(--accent-cyan);
}

.playstore-icon {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
}

.playstore-text {
  display: flex;
  flex-direction: column;
  text-align: left;
}

.playstore-sub {
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #94a3b8;
  line-height: 1;
}

.playstore-main {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.2;
}

/* Mobile Menu Toggle */
.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 6px;
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero {
  position: relative;
  padding: 80px 0 90px;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 500px;
  background: var(--gradient-hero-glow);
  pointer-events: none;
  z-index: 0;
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 50px;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.pill-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  color: var(--accent-cyan);
  font-size: 0.84rem;
  font-weight: 600;
  width: fit-content;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-emerald);
  box-shadow: 0 0 8px var(--accent-emerald);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.7; }
  50% { transform: scale(1.3); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.7; }
}

.hero-title {
  font-size: clamp(2.4rem, 4.8vw, 3.8rem);
  font-weight: 800;
  line-height: 1.12;
}

.hero-lead {
  font-size: 1.16rem;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.65;
}

.hero-stats-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
  padding: 16px 0;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.stat-chip {
  display: flex;
  align-items: center;
  gap: 10px;
}

.stat-chip-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-cyan);
}

.stat-chip-text strong {
  display: block;
  font-size: 1rem;
  line-height: 1.1;
  color: var(--text-primary);
}

.stat-chip-text span {
  font-size: 0.76rem;
  color: var(--text-muted);
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  padding-top: 8px;
}

.qr-trigger-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  cursor: pointer;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast);
}

.qr-trigger-btn:hover {
  color: var(--accent-cyan);
}

/* Hero Visual / Mockup */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.phone-mockup-wrapper {
  position: relative;
  width: 300px;
  max-width: 100%;
}

.phone-frame {
  position: relative;
  border: 10px solid #1e293b;
  border-radius: 42px;
  background: #000;
  overflow: hidden;
  box-shadow: 0 25px 60px -15px rgba(0, 0, 0, 0.8), 0 0 35px rgba(99, 102, 241, 0.25);
  aspect-ratio: 9 / 19.5;
}

.phone-notch {
  position: absolute;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 14px;
  background: #1e293b;
  border-radius: 12px;
  z-index: 10;
}

.phone-screen-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* Floating Badges on Hero Phone */
.floating-badge {
  position: absolute;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  padding: 12px 16px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 12px;
  z-index: 15;
  animation: float 4s ease-in-out infinite alternate;
}

.badge-left {
  top: 25%;
  left: -48px;
  animation-delay: 0.5s;
}

.badge-right {
  bottom: 22%;
  right: -42px;
  animation-delay: 1.8s;
}

@keyframes float {
  0% { transform: translateY(0px); }
  100% { transform: translateY(-12px); }
}

.badge-icon-box {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
}

.badge-icon-box.purple {
  background: rgba(139, 92, 246, 0.15);
  color: var(--accent-purple);
}

.badge-info h5 {
  font-size: 0.88rem;
  font-weight: 700;
  line-height: 1.1;
}

.badge-info p {
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* ==========================================================================
   INTERACTIVE SPEED DRILL SECTION
   ========================================================================== */
.section-drill {
  padding: 90px 0;
  background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 50%, var(--bg-primary) 100%);
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 50px;
}

.section-tag {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent-cyan);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.9rem, 3.4vw, 2.7rem);
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
}

/* Drill Game Box */
.drill-arena {
  max-width: 760px;
  margin: 0 auto;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 36px;
  backdrop-filter: blur(20px);
  box-shadow: var(--shadow-lg), 0 0 40px rgba(99, 102, 241, 0.15);
  position: relative;
  overflow: hidden;
}

.drill-glow-effect {
  position: absolute;
  top: -100px;
  right: -100px;
  width: 250px;
  height: 250px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.25), transparent 70%);
  pointer-events: none;
}

/* Mode Switcher Tabs */
.drill-tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 28px;
  flex-wrap: wrap;
}

.drill-tab-btn {
  padding: 8px 18px;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.drill-tab-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-focus);
}

.drill-tab-btn.active {
  background: var(--gradient-brand);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
}

/* Drill Status Bar */
.drill-statusbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  margin-bottom: 24px;
}

.drill-stat-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.92rem;
  font-weight: 600;
}

.drill-stat-item span {
  color: var(--text-muted);
  font-weight: 500;
}

.streak-counter {
  color: var(--accent-amber);
  display: flex;
  align-items: center;
  gap: 4px;
}

/* Timer Progress Bar */
.timer-track {
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-full);
  margin-bottom: 28px;
  overflow: hidden;
}

.timer-fill {
  height: 100%;
  width: 100%;
  background: var(--gradient-accent);
  border-radius: var(--radius-full);
  transition: width 0.1s linear, background-color 0.3s ease;
}

.timer-fill.danger {
  background: var(--accent-rose);
}

/* Card Question Area */
.quiz-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.question-box {
  min-height: 120px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin-bottom: 28px;
}

.question-label {
  font-size: 0.84rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 6px;
}

.question-expression {
  font-size: clamp(2.2rem, 5vw, 3.2rem);
  font-weight: 800;
  color: var(--text-primary);
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
}

/* Answers Grid */
.answers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  width: 100%;
  max-width: 480px;
  margin-bottom: 24px;
}

.answer-btn {
  padding: 16px 20px;
  font-size: 1.25rem;
  font-weight: 700;
  font-family: var(--font-mono);
  background: var(--bg-tertiary);
  border: 2px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.14s ease;
}

.answer-btn:hover:not(:disabled) {
  border-color: var(--accent-cyan);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
}

.answer-btn.correct {
  background: rgba(16, 185, 129, 0.25) !important;
  border-color: var(--accent-emerald) !important;
  color: var(--accent-emerald) !important;
  transform: scale(1.03);
}

.answer-btn.wrong {
  background: rgba(244, 63, 94, 0.25) !important;
  border-color: var(--accent-rose) !important;
  color: var(--accent-rose) !important;
  animation: shake 0.3s;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}

/* Start / Results Screens inside game */
.start-screen, .result-screen {
  text-align: center;
  padding: 20px 0;
}

.start-screen h3, .result-screen h3 {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.start-screen p, .result-screen p {
  color: var(--text-secondary);
  margin-bottom: 24px;
  max-width: 440px;
  margin-left: auto;
  margin-right: auto;
}

.result-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  background: rgba(16, 185, 129, 0.15);
  border: 1px solid var(--accent-emerald);
  border-radius: var(--radius-full);
  color: var(--accent-emerald);
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.result-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 20px 0 28px;
}

.metric-card {
  background: var(--bg-tertiary);
  padding: 16px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
}

.metric-num {
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--accent-cyan);
  font-family: var(--font-mono);
}

.metric-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-top: 4px;
}

/* ==========================================================================
   EXAM TIME-SAVED & ROI CALCULATOR
   ========================================================================== */
.section-calculator {
  padding: 80px 0;
  position: relative;
}

.calc-wrapper {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  backdrop-filter: blur(20px);
  padding: 40px;
  box-shadow: var(--shadow-lg);
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
}

.calc-controls {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.calc-group label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.96rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.calc-val-pill {
  background: var(--bg-tertiary);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  color: var(--accent-cyan);
  font-family: var(--font-mono);
  font-size: 0.88rem;
  border: 1px solid var(--border-subtle);
}

/* Exam Buttons Selector */
.exam-select-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.exam-btn {
  padding: 10px 14px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.exam-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-focus);
}

.exam-btn.active {
  background: rgba(99, 102, 241, 0.18);
  border-color: var(--accent-indigo);
  color: var(--text-primary);
}

/* Slider Style */
.custom-range {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 8px;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  outline: none;
  cursor: pointer;
}

.custom-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent-cyan);
  cursor: pointer;
  box-shadow: 0 0 10px var(--accent-cyan);
  transition: transform var(--transition-fast);
}

.custom-range::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

/* Output Showcase Card */
.calc-display-card {
  background: linear-gradient(145deg, rgba(99, 102, 241, 0.12), rgba(6, 182, 212, 0.08));
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
  position: relative;
}

.calc-display-card h4 {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.time-big-num {
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  font-weight: 800;
  font-family: var(--font-mono);
  line-height: 1;
  color: var(--accent-emerald);
  margin-bottom: 8px;
  text-shadow: 0 0 30px rgba(16, 185, 129, 0.35);
}

.time-unit {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.calc-explanation {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin: 20px 0;
  line-height: 1.5;
}

.exam-advantage-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  text-align: left;
  border-top: 1px solid var(--border-subtle);
  padding-top: 16px;
  margin-top: 16px;
}

.exam-advantage-list li {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.advantage-check {
  color: var(--accent-emerald);
  font-weight: bold;
}

/* ==========================================================================
   FEATURE MODULES GRID
   ========================================================================== */
.section-features {
  padding: 90px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-brand);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.feature-card:hover {
  transform: translateY(-6px);
  background: var(--bg-card-hover);
  border-color: var(--border-focus);
  box-shadow: var(--shadow-md);
}

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

.feature-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: var(--accent-cyan);
  margin-bottom: 20px;
}

.feature-card:nth-child(2) .feature-icon-box {
  background: rgba(16, 185, 129, 0.12);
  border-color: rgba(16, 185, 129, 0.25);
  color: var(--accent-emerald);
}

.feature-card:nth-child(3) .feature-icon-box {
  background: rgba(139, 92, 246, 0.12);
  border-color: rgba(139, 92, 246, 0.25);
  color: var(--accent-purple);
}

.feature-card:nth-child(4) .feature-icon-box {
  background: rgba(245, 158, 11, 0.12);
  border-color: rgba(245, 158, 11, 0.25);
  color: var(--accent-amber);
}

.feature-card:nth-child(5) .feature-icon-box {
  background: rgba(6, 182, 212, 0.12);
  border-color: rgba(6, 182, 212, 0.25);
  color: var(--accent-cyan);
}

.feature-card:nth-child(6) .feature-icon-box {
  background: rgba(244, 63, 94, 0.12);
  border-color: rgba(244, 63, 94, 0.25);
  color: var(--accent-rose);
}

.feature-card h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.94rem;
  line-height: 1.6;
  margin-bottom: 18px;
}

.feature-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.f-chip {
  font-size: 0.74rem;
  font-weight: 600;
  padding: 4px 10px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  color: var(--text-muted);
}

/* ==========================================================================
   APP SCREENSHOTS SHOWCASE
   ========================================================================== */
.section-screenshots {
  padding: 90px 0;
  background: var(--bg-secondary);
}

.screenshot-carousel-container {
  position: relative;
  overflow: hidden;
  padding: 20px 0 40px;
}

.screenshot-track {
  display: flex;
  gap: 24px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  padding: 10px 4px 20px;
}

.screenshot-track::-webkit-scrollbar {
  height: 6px;
}

.screenshot-track::-webkit-scrollbar-thumb {
  background: var(--border-subtle);
  border-radius: var(--radius-full);
}

.screenshot-item {
  flex: 0 0 280px;
  scroll-snap-align: center;
  transition: transform var(--transition-normal);
  cursor: pointer;
}

.screenshot-card {
  background: #000000;
  border: 6px solid #1e293b;
  border-radius: 26px;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  aspect-ratio: 9 / 19;
  position: relative;
}

.screenshot-item:hover .screenshot-card {
  transform: translateY(-8px);
  border-color: var(--accent-cyan);
  box-shadow: 0 15px 35px rgba(6, 182, 212, 0.25);
}

.screenshot-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.screenshot-caption {
  text-align: center;
  margin-top: 14px;
}

.screenshot-caption h4 {
  font-size: 1rem;
  margin-bottom: 4px;
}

.screenshot-caption p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ==========================================================================
   ANALYTICS & WEAK SPOT SPOTLIGHT
   ========================================================================== */
.section-analytics {
  padding: 90px 0;
}

.analytics-banner {
  background: linear-gradient(135deg, rgba(19, 27, 46, 0.95), rgba(13, 18, 31, 0.9));
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 50px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.analytics-content h2 {
  font-size: clamp(1.9rem, 3.2vw, 2.5rem);
  margin-bottom: 16px;
}

.analytics-content p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 28px;
}

.analytics-features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.analytics-list-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
}

.check-circle {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.analytics-list-item h4 {
  font-size: 1rem;
  margin-bottom: 2px;
}

.analytics-list-item p {
  font-size: 0.86rem;
  color: var(--text-muted);
  margin-bottom: 0;
}

/* Mock Dashboard Visual */
.mock-dashboard {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-lg);
}

.mock-dash-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 20px;
}

.mock-avatar {
  display: flex;
  align-items: center;
  gap: 10px;
}

.avatar-circle {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--gradient-brand);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #fff;
}

.mock-grid-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-bottom: 20px;
}

.mock-stat {
  background: var(--bg-primary);
  padding: 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
}

.mock-stat-val {
  font-size: 1.4rem;
  font-weight: 800;
  font-family: var(--font-mono);
  color: var(--accent-cyan);
}

.mock-stat-lbl {
  font-size: 0.74rem;
  color: var(--text-muted);
}

.weak-spot-bar {
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  padding: 14px;
  border: 1px solid var(--border-subtle);
}

.weak-spot-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  margin-bottom: 8px;
  font-weight: 600;
}

.weak-spot-progress {
  height: 8px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.weak-spot-fill {
  height: 100%;
  width: 94%;
  background: var(--gradient-accent);
}

/* ==========================================================================
   TARGET EXAMS COMPARISON
   ========================================================================== */
.section-exams {
  padding: 90px 0;
  background: var(--bg-secondary);
}

.exams-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.exam-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 28px 22px;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.exam-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-focus);
  background: var(--bg-card-hover);
}

.exam-badge-top {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-indigo);
  width: fit-content;
  margin-bottom: 14px;
}

.exam-card h3 {
  font-size: 1.25rem;
  margin-bottom: 8px;
}

.exam-target-desc {
  font-size: 0.86rem;
  color: var(--text-muted);
  margin-bottom: 18px;
}

.exam-bullet-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: auto;
  border-top: 1px solid var(--border-subtle);
  padding-top: 16px;
}

.exam-bullet-list li {
  font-size: 0.84rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.exam-bullet-list li::before {
  content: '⚡';
  font-size: 0.8rem;
}

/* ==========================================================================
   TESTIMONIALS & SOCIAL PROOF
   ========================================================================== */
.section-testimonials {
  padding: 90px 0;
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.testimonial-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 30px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 20px;
  transition: all var(--transition-normal);
}

.testimonial-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-focus);
}

.star-rating {
  color: #fbbf24;
  font-size: 1.1rem;
  letter-spacing: 2px;
}

.testimonial-quote {
  font-size: 0.96rem;
  color: var(--text-secondary);
  line-height: 1.6;
  font-style: italic;
}

.author-info {
  display: flex;
  align-items: center;
  gap: 12px;
}

.author-pic {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: var(--accent-cyan);
}

.author-details h4 {
  font-size: 0.95rem;
  margin-bottom: 2px;
}

.author-details p {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ==========================================================================
   FAQ SECTION
   ========================================================================== */
.section-faq {
  padding: 90px 0;
  background: var(--bg-secondary);
}

.faq-container {
  max-width: 780px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item.active {
  border-color: var(--border-focus);
}

.faq-question {
  padding: 20px 24px;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.05rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  gap: 16px;
}

.faq-icon {
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast);
  color: var(--accent-cyan);
  flex-shrink: 0;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 24px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.faq-item.active .faq-answer {
  padding: 0 24px 22px 24px;
  max-height: 220px;
}

/* ==========================================================================
   CTA BANNER & FOOTER
   ========================================================================== */
.section-cta {
  padding: 100px 0;
  position: relative;
}

.cta-box {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.25) 0%, rgba(6, 182, 212, 0.2) 100%), var(--bg-card);
  border: 1px solid rgba(99, 102, 241, 0.4);
  border-radius: var(--radius-xl);
  padding: 60px 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-glow);
}

.cta-box h2 {
  font-size: clamp(2.1rem, 4vw, 3.2rem);
  margin-bottom: 16px;
}

.cta-box p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 580px;
  margin: 0 auto 36px;
}

.cta-actions {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 60px 0 30px;
  background: var(--bg-primary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 12px;
  max-width: 320px;
}

.footer-col h5 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.88rem;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 12px;
}

/* ==========================================================================
   QR CODE MODAL
   ========================================================================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  z-index: 999;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.modal-overlay.open {
  display: flex;
  opacity: 1;
}

.modal-content {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 36px;
  max-width: 400px;
  width: 100%;
  text-align: center;
  position: relative;
  box-shadow: var(--shadow-lg);
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.4rem;
  cursor: pointer;
}

.modal-close:hover {
  color: var(--text-primary);
}

.qr-code-box {
  background: #ffffff;
  padding: 16px;
  border-radius: var(--radius-md);
  display: inline-block;
  margin: 20px 0;
  box-shadow: var(--shadow-sm);
}

.qr-code-box img {
  display: block;
  width: 180px;
  height: 180px;
}

/* ==========================================================================
   MOBILE FLOATING CTA
   ========================================================================== */
.mobile-sticky-cta {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  border-top: 1px solid var(--border-subtle);
  padding: 12px 20px;
  display: none;
  align-items: center;
  justify-content: space-between;
  z-index: 90;
  transform: translateY(100%);
  transition: transform var(--transition-normal);
}

.mobile-sticky-cta.visible {
  transform: translateY(0);
}

/* ==========================================================================
   RESPONSIVE BREAKPOINTS
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    align-items: center;
  }

  .hero-stats-row {
    justify-content: center;
  }

  .hero-cta-group {
    justify-content: center;
  }

  .badge-left {
    left: -10px;
  }

  .badge-right {
    right: -10px;
  }

  .calc-wrapper {
    grid-template-columns: 1fr;
  }

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

  .analytics-banner {
    grid-template-columns: 1fr;
  }

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

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

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

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 74px;
    left: 0;
    right: 0;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 24px 28px;
    gap: 18px;
    border-bottom: 1px solid var(--border-subtle);
    box-shadow: var(--shadow-lg);
    z-index: 99;
  }

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

  .mobile-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    border-radius: var(--radius-sm);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
  }

  #nav-download-btn span {
    display: none;
  }

  #nav-download-btn {
    padding: 10px 14px;
  }

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

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

  .drill-arena {
    padding: 24px 16px;
  }

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

  .result-metrics {
    grid-template-columns: 1fr;
  }

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

  .mobile-sticky-cta {
    display: flex;
  }
}