/* ==========================================================================
   StudyOS — Design System & Global Styles
   Onyx Dark Surface (#0A0B0E) & Warm Amber Gold (#F59E0B)
   ========================================================================== */

:root {
  /* Color Palette - Premium Onyx & Amber */
  --bg: #0A0B0E;
  --bg-subtle: #0F1117;
  --surface-1: #13161F;
  --surface-2: #1A1E29;
  --surface-3: #232838;
  --surface-glass: rgba(19, 22, 31, 0.75);
  --surface-glass-hover: rgba(26, 30, 41, 0.88);
  --surface-glass-strong: rgba(15, 17, 23, 0.92);

  --border: rgba(255, 255, 255, 0.08);
  --border-subtle: rgba(255, 255, 255, 0.04);
  --border-hover: rgba(255, 255, 255, 0.16);
  --border-accent: rgba(245, 158, 11, 0.4);
  --border-accent-subtle: rgba(245, 158, 11, 0.2);

  --text-primary: #F9FAFB;
  --text-secondary: #9CA3AF;
  --text-muted: #6B7280;
  --text-inverse: #0A0B0E;

  --accent: #F59E0B;
  --accent-light: #FBBF24;
  --accent-hover: #D97706;
  --accent-dark: #B45309;
  --accent-glow: rgba(245, 158, 11, 0.25);
  --accent-surface: rgba(245, 158, 11, 0.1);

  --success: #10B981;
  --success-glow: rgba(16, 185, 129, 0.25);
  --error: #EF4444;
  --error-glow: rgba(239, 68, 68, 0.25);
  --cyan: #06B6D4;
  --cyan-glow: rgba(6, 182, 212, 0.25);

  /* Typography */
  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Layout & Radii */
  --radius-xs: 6px;
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 22px;
  --radius-xl: 30px;
  --radius-pill: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.6);
  --shadow-glass: 0 20px 48px -10px rgba(0, 0, 0, 0.7);
  --shadow-accent: 0 0 32px rgba(245, 158, 11, 0.28);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg);
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  position: relative;
}

/* Ambient Floating Glow Mesh */
.ambient-mesh {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.ambient-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.4;
  transition: transform 12s ease;
}

.ambient-orb-1 {
  top: -10%;
  left: 30%;
  width: 550px;
  height: 550px;
  background: radial-gradient(circle, rgba(245, 158, 11, 0.16) 0%, transparent 70%);
  animation: floatOrb1 20s infinite alternate ease-in-out;
}

.ambient-orb-2 {
  top: 40%;
  right: -5%;
  width: 480px;
  height: 480px;
  background: radial-gradient(circle, rgba(217, 119, 6, 0.12) 0%, transparent 70%);
  animation: floatOrb2 25s infinite alternate ease-in-out;
}

.ambient-orb-3 {
  bottom: 10%;
  left: -10%;
  width: 520px;
  height: 520px;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.08) 0%, transparent 70%);
  animation: floatOrb3 22s infinite alternate ease-in-out;
}

@keyframes floatOrb1 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(60px, 80px) scale(1.15); }
}
@keyframes floatOrb2 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(-80px, -50px) scale(1.1); }
}
@keyframes floatOrb3 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(50px, -70px) scale(1.08); }
}

/* Top Banner Announcement */
.top-announcement {
  background: linear-gradient(90deg, rgba(245, 158, 11, 0.15), rgba(217, 119, 6, 0.08), rgba(245, 158, 11, 0.15));
  border-bottom: 1px solid var(--border-accent-subtle);
  padding: 8px 16px;
  font-size: 0.85rem;
  text-align: center;
  position: relative;
  z-index: 1002;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.announcement-badge {
  background: var(--accent);
  color: var(--text-inverse);
  font-weight: 700;
  font-size: 0.7rem;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.top-announcement a {
  color: var(--accent-light);
  text-decoration: none;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.top-announcement a:hover {
  text-decoration: underline;
}

/* Floating Sticky Navigation Bar */
.nav-wrapper {
  position: sticky;
  top: 14px;
  z-index: 1000;
  padding: 0 16px;
  display: flex;
  justify-content: center;
}

.navbar {
  width: 100%;
  max-width: 1120px;
  background: var(--surface-glass);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: var(--shadow-glass);
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.navbar.scrolled {
  border-color: rgba(245, 158, 11, 0.3);
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.7), 0 0 20px rgba(245, 158, 11, 0.1);
  background: rgba(14, 17, 24, 0.88);
}

/* Brand / Logo */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  position: relative;
}

.brand-icon {
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #2A200B 0%, #17140B 100%);
  border: 1px solid var(--accent);
  box-shadow: 0 0 14px var(--accent-glow);
  position: relative;
  overflow: hidden;
}

.brand-icon img {
  width: 22px;
  height: 22px;
  object-fit: contain;
}

.brand-icon svg {
  width: 18px;
  height: 18px;
  color: var(--accent);
}

.brand-tag {
  font-size: 0.68rem;
  font-weight: 700;
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: var(--accent);
  padding: 2px 7px;
  border-radius: var(--radius-pill);
  letter-spacing: 0.03em;
  font-family: var(--font-mono);
}

/* Navigation Links */
.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  transition: all 0.2s ease;
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.nav-link:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

.nav-link.active {
  color: var(--accent-light);
  background: rgba(245, 158, 11, 0.12);
  font-weight: 600;
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 2px;
  background: var(--accent);
  border-radius: var(--radius-pill);
  box-shadow: 0 0 8px var(--accent);
}

.nav-badge-new {
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--accent);
  background: rgba(245, 158, 11, 0.18);
  border: 1px solid rgba(245, 158, 11, 0.4);
  padding: 1px 6px;
  border-radius: var(--radius-pill);
  text-transform: uppercase;
}

/* Action Area in Navbar */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.btn-nav-download {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
  color: var(--text-inverse);
  text-decoration: none;
  font-weight: 700;
  font-size: 0.88rem;
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.35);
  display: inline-flex;
  align-items: center;
  gap: 7px;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-nav-download:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(245, 158, 11, 0.5);
  background: linear-gradient(135deg, #FBBF24 0%, var(--accent) 100%);
}

.btn-nav-download svg {
  width: 16px;
  height: 16px;
}

/* Mobile Hamburger Toggle */
.mobile-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--text-primary);
  padding: 8px;
  border-radius: var(--radius-sm);
}

.mobile-toggle svg {
  width: 24px;
  height: 24px;
  display: block;
}

/* Mobile Navigation Drawer */
.mobile-drawer {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(10, 11, 14, 0.96);
  backdrop-filter: blur(28px);
  -webkit-backdrop-filter: blur(28px);
  z-index: 2000;
  display: flex;
  flex-direction: column;
  padding: 32px 24px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.mobile-drawer.open {
  opacity: 1;
  pointer-events: auto;
}

.drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 40px;
}

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

.drawer-link {
  color: var(--text-primary);
  font-size: 1.3rem;
  font-weight: 600;
  text-decoration: none;
  padding: 12px 16px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.drawer-link.active {
  color: var(--accent);
  border-color: var(--border-accent);
  background: rgba(245, 158, 11, 0.08);
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

.container-narrow {
  max-width: 900px;
}

/* General Section Structure */
.section {
  padding: 90px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 56px auto;
}

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 14px;
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.25);
  padding: 4px 14px;
  border-radius: var(--radius-pill);
}

.section-title {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.section-description {
  font-size: 1.12rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* Gradient Text Utilities */
.text-gradient-gold {
  background: linear-gradient(135deg, #FDE68A 0%, #F59E0B 50%, #D97706 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.text-gradient-silver {
  background: linear-gradient(135deg, #FFFFFF 0%, #E5E7EB 50%, #9CA3AF 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Hero Section */
.hero-section {
  padding: 70px 0 90px 0;
  text-align: center;
  position: relative;
}

.hero-pill-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(22, 26, 36, 0.7);
  border: 1px solid rgba(245, 158, 11, 0.35);
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  color: var(--text-primary);
  margin-bottom: 24px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}

.hero-pill-badge .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent);
  animation: pulseDot 2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.hero-title {
  font-size: 3.8rem;
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.035em;
  max-width: 980px;
  margin: 0 auto 24px auto;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 auto 36px auto;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.btn-primary-hero {
  background: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
  color: #0A0B0E;
  font-weight: 800;
  font-size: 1.05rem;
  padding: 15px 32px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  box-shadow: 0 8px 26px rgba(245, 158, 11, 0.38);
  border: 1px solid rgba(255, 255, 255, 0.25);
  transition: all 0.28s cubic-bezier(0.16, 1, 0.3, 1);
}

.btn-primary-hero:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 34px rgba(245, 158, 11, 0.55);
  background: linear-gradient(135deg, #FBBF24 0%, #F59E0B 100%);
}

.btn-secondary-hero {
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1.05rem;
  padding: 15px 28px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--border);
  transition: all 0.25s ease;
}

.btn-secondary-hero:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--border-hover);
  color: var(--accent-light);
}

.hero-meta-strip {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.hero-meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.hero-meta-item svg {
  width: 14px;
  height: 14px;
  color: var(--accent);
}

/* Hero Interactive Timer Box */
.hero-timer-box {
  margin: 50px auto 0 auto;
  max-width: 820px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 32px;
  box-shadow: var(--shadow-glass);
  position: relative;
  overflow: hidden;
}

.hero-timer-box::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
}

.hero-timer-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 32px;
  align-items: center;
  text-align: left;
}

/* Interactive SVG Timer Widget */
.timer-widget-display {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.timer-svg-container {
  position: relative;
  width: 220px;
  height: 220px;
}

.timer-svg-container svg {
  transform: rotate(-90deg);
  width: 100%;
  height: 100%;
}

.timer-track {
  stroke: rgba(255, 255, 255, 0.06);
  stroke-width: 10;
  fill: none;
}

.timer-progress {
  stroke: var(--accent);
  stroke-width: 10;
  fill: none;
  stroke-linecap: round;
  transition: stroke-dashoffset 0.5s ease;
  filter: drop-shadow(0 0 8px rgba(245, 158, 11, 0.5));
}

.timer-center-info {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}

.timer-digital-clock {
  font-family: var(--font-mono);
  font-size: 2.8rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  line-height: 1;
  margin-bottom: 4px;
}

.timer-phase-badge {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent);
  background: rgba(245, 158, 11, 0.15);
  padding: 3px 8px;
  border-radius: var(--radius-pill);
  display: inline-block;
}

.timer-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 16px;
}

.timer-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.88rem;
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s ease;
}

.timer-btn:hover {
  border-color: var(--border-hover);
  background: var(--surface-3);
}

.timer-btn.btn-start {
  background: var(--accent);
  color: var(--text-inverse);
  border-color: var(--accent);
  font-weight: 700;
}

.timer-btn.btn-start:hover {
  background: var(--accent-light);
}

.timer-preset-chips {
  display: flex;
  gap: 6px;
  margin-top: 14px;
}

.preset-chip {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all 0.2s ease;
}

.preset-chip:hover, .preset-chip.active {
  color: var(--accent);
  border-color: var(--border-accent);
  background: rgba(245, 158, 11, 0.08);
}

/* Timer explanation copy */
.timer-details {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.timer-feature-tag {
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.timer-title {
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1.25;
}

.timer-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.timer-checklist {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 4px;
}

.timer-checklist li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.timer-checklist li svg {
  width: 16px;
  height: 16px;
  color: var(--success);
  flex-shrink: 0;
}

/* Card Grid Layouts */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

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

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

/* Spotlight Card Base */
.spotlight-card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 30px;
  position: relative;
  overflow: hidden;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), border-color 0.3s ease, box-shadow 0.3s ease;
}

.spotlight-card:hover {
  transform: translateY(-4px);
  border-color: rgba(245, 158, 11, 0.35);
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.5), 0 0 24px rgba(245, 158, 11, 0.08);
}

.spotlight-card::before {
  content: '';
  position: absolute;
  top: var(--mouse-y, -100px);
  left: var(--mouse-x, -100px);
  width: 250px;
  height: 250px;
  background: radial-gradient(circle, rgba(245, 158, 11, 0.12) 0%, transparent 70%);
  transform: translate(-50%, -50%);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.4s ease;
}

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

.card-icon-badge {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--accent);
}

.card-icon-badge svg {
  width: 24px;
  height: 24px;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.card-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
}

.card-link {
  color: var(--accent);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: gap 0.2s ease;
}

.card-link:hover {
  gap: 9px;
  color: var(--accent-light);
}

/* Interactive Tabs / Feature Switcher */
.feature-tabs-container {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 32px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 32px;
  box-shadow: var(--shadow-glass);
}

.tab-nav-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tab-btn {
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  padding: 14px 18px;
  text-align: left;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 14px;
}

.tab-btn:hover {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--border-subtle);
}

.tab-btn.active {
  background: var(--surface-2);
  border-color: var(--border-accent);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}

.tab-btn-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.04);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: all 0.2s ease;
}

.tab-btn.active .tab-btn-icon {
  background: rgba(245, 158, 11, 0.15);
  color: var(--accent);
}

.tab-btn-content h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.tab-btn.active h4 {
  color: var(--accent-light);
}

.tab-btn-content p {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.tab-panel-viewport {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.tab-panel {
  display: none;
  animation: fadeInPanel 0.35s ease forwards;
}

.tab-panel.active {
  display: block;
}

@keyframes fadeInPanel {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Interactive Simulator: Exam Readiness Engine */
.readiness-simulator-card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 36px;
  box-shadow: var(--shadow-glass);
}

.simulator-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 36px;
  align-items: center;
}

.slider-group {
  margin-bottom: 20px;
}

.slider-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 8px;
  font-size: 0.92rem;
  font-weight: 600;
}

.slider-val {
  font-family: var(--font-mono);
  color: var(--accent);
}

.range-input {
  width: 100%;
  height: 6px;
  border-radius: var(--radius-pill);
  background: var(--surface-3);
  outline: none;
  -webkit-appearance: none;
  appearance: none;
}

.range-input::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  box-shadow: 0 0 10px var(--accent);
  transition: transform 0.15s ease;
}

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

.simulator-result-box {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  text-align: center;
  position: relative;
}

.result-index-number {
  font-size: 4.5rem;
  font-weight: 800;
  font-family: var(--font-mono);
  line-height: 1;
  margin-bottom: 8px;
}

.readiness-badge-display {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  font-weight: 700;
  font-size: 0.88rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 18px;
}

/* Interactive Mistake Bank Categorizer */
.mistake-explorer-container {
  margin-top: 32px;
}

.mistake-chips {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 24px;
}

.mistake-chip {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all 0.2s ease;
}

.mistake-chip:hover {
  border-color: var(--border-hover);
  color: var(--text-primary);
}

.mistake-chip.active {
  background: rgba(239, 68, 68, 0.15);
  border-color: var(--error);
  color: #FCA5A5;
}

.mistake-detail-card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  max-width: 760px;
  margin: 0 auto;
}

/* Comparison Table */
.comparison-container {
  overflow-x: auto;
  border-radius: var(--radius-xl);
  border: 1px solid var(--border);
  background: var(--surface-1);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 680px;
}

.comparison-table th,
.comparison-table td {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
}

.comparison-table th {
  background: var(--surface-2);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-primary);
}

.comparison-table td {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.comparison-table tr:hover td {
  background: rgba(255, 255, 255, 0.015);
}

.comparison-table .highlight-col {
  background: rgba(245, 158, 11, 0.04);
  color: var(--text-primary);
  font-weight: 600;
  border-left: 1px solid var(--border-accent-subtle);
  border-right: 1px solid var(--border-accent-subtle);
}

/* FAQ Accordion */
.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.25s ease;
}

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

.faq-item.open {
  border-color: var(--border-accent);
}

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

.faq-toggle-icon {
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: transform 0.25s ease;
  flex-shrink: 0;
}

.faq-item.open .faq-toggle-icon {
  transform: rotate(45deg);
  color: var(--accent);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0.16, 1, 0.3, 1), padding 0.3s ease;
  padding: 0 24px;
  color: var(--text-secondary);
  font-size: 0.98rem;
  line-height: 1.65;
}

.faq-item.open .faq-answer {
  max-height: 400px;
  padding: 0 24px 22px 24px;
}

/* Download Hub Card & Verification */
.download-card-hero {
  background: linear-gradient(135deg, rgba(24, 28, 38, 0.9) 0%, rgba(15, 17, 23, 0.95) 100%);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-xl);
  padding: 44px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.7), 0 0 30px rgba(245, 158, 11, 0.12);
  text-align: center;
  position: relative;
  overflow: hidden;
  max-width: 820px;
  margin: 0 auto;
}

.download-card-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, #F59E0B, #FBBF24, #D97706);
}

.checksum-box {
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 12px 18px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin: 20px 0;
  word-break: break-all;
}

.copy-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-primary);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.copy-btn:hover {
  background: var(--accent);
  color: var(--text-inverse);
  border-color: var(--accent);
}

/* Footer */
.site-footer {
  background: var(--surface-subtle);
  border-top: 1px solid var(--border);
  padding: 70px 0 40px 0;
  margin-top: 90px;
  position: relative;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 50px;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.6;
  margin-top: 14px;
  max-width: 320px;
}

.footer-col h5 {
  font-size: 0.88rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-primary);
  margin-bottom: 18px;
}

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

.footer-col a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.92rem;
  transition: color 0.2s ease;
}

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-subtle);
  padding-top: 30px;
  font-size: 0.85rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 16px;
}

.footer-badge-offline {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--success);
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 0.78rem;
}

/* Animations / Scroll Reveal */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1), transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

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

/* Responsive Media Queries */
@media (max-width: 968px) {
  .hero-title {
    font-size: 2.8rem;
  }
  .section-title {
    font-size: 2rem;
  }
  .grid-3 {
    grid-template-columns: 1fr;
  }
  .grid-2 {
    grid-template-columns: 1fr;
  }
  .feature-tabs-container {
    grid-template-columns: 1fr;
  }
  .hero-timer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .timer-details {
    align-items: center;
  }
  .simulator-grid {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
}

@media (max-width: 768px) {
  .nav-links, .nav-actions {
    display: none;
  }
  .mobile-toggle {
    display: block;
  }
  .hero-title {
    font-size: 2.2rem;
  }
  .hero-subtitle {
    font-size: 1.05rem;
  }
  .section {
    padding: 60px 0;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
}