/* ==========================================================================
   CalcOS — TI-84 Graphing Calculator Online
   Main Stylesheet
   
   TABLE OF CONTENTS:
   1.  CSS Custom Properties (Design Tokens)
   2.  CSS Reset & Base Styles
   3.  Background Effects (Grid + Noise)
   4.  Navigation Bar
   5.  Hero Section
   6.  Glow Orb Decorations
   7.  Hero Stats Counter
   8.  Calculator Preview Window
   9.  Calculator Keypad & Buttons
   10. Section Shared Styles
   11. Features Grid
   12. How It Works Section
   13. Who Uses It Section
   14. FAQ Accordion
   15. Embed Code Section
   16. CTA (Call-to-Action) Section
   17. Footer
   18. Scroll Reveal Animation
   19. Keyframe Animations
   20. Responsive / Media Queries
   21. Custom Scrollbar
   ========================================================================== */


/* ==========================================================================
   1. CSS Custom Properties (Design Tokens)
   ========================================================================== */
:root {
  --bg: #0a0a0f;
  --surface: #111118;
  --surface2: #17171f;
  --border: rgba(255,255,255,0.07);
  --accent: #00e5ff;
  --accent2: #7c3aed;
  --accent3: #f59e0b;
  --text: #f0f0f5;
  --muted: #6b6b80;
  --grid: rgba(0,229,255,0.04);
}


/* ==========================================================================
   2. CSS Reset & Base Styles
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'DM Sans', sans-serif;
  overflow-x: hidden;
  min-height: 100vh;
}


/* ==========================================================================
   3. Background Effects (Grid + Noise)
   ========================================================================== */

/* Subtle dot-grid background to evoke graph paper / calculator display */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: 0;
}

/* Noise texture overlay for depth and tactility */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 512 512' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
  opacity: 0.4;
}


/* ==========================================================================
   4. Navigation Bar
   ========================================================================== */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 5%;
  height: 70px;
  background: rgba(10,10,15,0.7);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s;
}

/* Logo with animated pulse dot */
.nav-logo {
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: 1.4rem;
  letter-spacing: -0.03em;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.nav-logo .dot {
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--accent);
  animation: pulse 2s ease-in-out infinite;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: color 0.2s;
}

.nav-links a:hover { color: var(--text); }

/* Primary CTA button in nav */
.nav-cta {
  background: var(--accent);
  color: #000 !important;
  padding: 8px 20px;
  border-radius: 6px;
  font-weight: 700 !important;
  font-size: 0.85rem !important;
  transition: box-shadow 0.2s, transform 0.2s !important;
}

.nav-cta:hover {
  box-shadow: 0 0 20px rgba(0,229,255,0.5) !important;
  transform: translateY(-1px);
  color: #000 !important;
}


/* ==========================================================================
   5. Hero Section
   ========================================================================== */
.hero {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 5% 80px;
  overflow: hidden;
}

/* Badge pill above the headline */
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border: 1px solid rgba(0,229,255,0.3);
  border-radius: 100px;
  font-size: 0.78rem;
  font-family: 'Space Mono', monospace;
  color: var(--accent);
  background: rgba(0,229,255,0.05);
  margin-bottom: 2rem;
  animation: fadeSlideUp 0.8s ease both;
}

.hero-badge::before {
  content: '';
  width: 6px; height: 6px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--accent);
}

/* Large headline — split into 2 display lines */
.hero-title {
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: clamp(3rem, 8vw, 7rem);
  line-height: 0.95;
  letter-spacing: -0.04em;
  margin-bottom: 1.5rem;
  animation: fadeSlideUp 0.8s ease 0.1s both;
}

.hero-title .line1 {
  display: block;
  color: var(--text);
}

.hero-title .line2 {
  display: block;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent2) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Subheadline paragraph */
.hero-sub {
  max-width: 560px;
  font-size: 1.15rem;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 2.5rem;
  animation: fadeSlideUp 0.8s ease 0.2s both;
}

/* Hero CTA buttons row */
.hero-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeSlideUp 0.8s ease 0.3s both;
}

/* Solid primary button */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 36px;
  background: var(--accent);
  color: #000;
  font-weight: 700;
  font-size: 1rem;
  border-radius: 8px;
  text-decoration: none;
  transition: all 0.25s;
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 40%, rgba(255,255,255,0.2));
  opacity: 0;
  transition: opacity 0.25s;
}

.btn-primary:hover {
  box-shadow: 0 0 40px rgba(0,229,255,0.5), 0 4px 20px rgba(0,0,0,0.4);
  transform: translateY(-2px);
}

.btn-primary:hover::before { opacity: 1; }

/* Ghost secondary button */
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 36px;
  background: transparent;
  color: var(--text);
  font-weight: 500;
  font-size: 1rem;
  border-radius: 8px;
  text-decoration: none;
  border: 1px solid var(--border);
  transition: all 0.25s;
}

.btn-secondary:hover {
  border-color: rgba(255,255,255,0.2);
  background: var(--surface);
  transform: translateY(-2px);
}


/* ==========================================================================
   6. Glow Orb Decorations
   ========================================================================== */

/* Abstract glowing blobs — pure CSS atmospheric depth */
.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
}

.orb1 {
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(0,229,255,0.12) 0%, transparent 70%);
  top: -100px; left: -100px;
  animation: orbFloat 8s ease-in-out infinite;
}

.orb2 {
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(124,58,237,0.15) 0%, transparent 70%);
  bottom: 0; right: -100px;
  animation: orbFloat 10s ease-in-out infinite reverse;
}

.orb3 {
  width: 300px; height: 300px;
  background: radial-gradient(circle, rgba(245,158,11,0.08) 0%, transparent 70%);
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  animation: orbFloat 6s ease-in-out infinite;
}


/* ==========================================================================
   7. Hero Stats Counter
   ========================================================================== */
.hero-stats {
  display: flex;
  gap: 3rem;
  justify-content: center;
  margin-top: 4rem;
  flex-wrap: wrap;
  animation: fadeSlideUp 0.8s ease 0.4s both;
}

.stat { text-align: center; }

.stat-num {
  font-family: 'Space Mono', monospace;
  font-size: 2rem;
  font-weight: 700;
  color: var(--text);
  display: block;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.stat-num .accent { color: var(--accent); }


/* ==========================================================================
   8. Calculator Preview Window
   ========================================================================== */
.calc-preview {
  position: relative;
  z-index: 1;
  padding: 80px 5%;
  display: flex;
  justify-content: center;
  animation: fadeSlideUp 0.8s ease 0.5s both;
}

/* macOS-style window chrome */
.calc-window {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  overflow: hidden;
  width: 100%;
  max-width: 900px;
  box-shadow:
    0 0 0 1px rgba(0,229,255,0.1),
    0 40px 120px rgba(0,0,0,0.8),
    0 0 80px rgba(0,229,255,0.05);
}

.calc-titlebar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--surface2);
}

/* Traffic-light window dots */
.calc-dot { width: 12px; height: 12px; border-radius: 50%; }
.dot-r { background: #ff5f57; }
.dot-y { background: #febc2e; }
.dot-g { background: #28c840; }

.calc-title {
  font-family: 'Space Mono', monospace;
  font-size: 0.75rem;
  color: var(--muted);
  margin-left: 8px;
}

/* Side-by-side: screen left | keypad right */
.calc-body {
  display: grid;
  grid-template-columns: 1fr 280px;
  min-height: 440px;
}

/* Calculator LCD screen area */
.calc-screen {
  background: #050810;
  padding: 24px;
  font-family: 'Space Mono', monospace;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
}

.calc-screen-top {
  font-size: 0.7rem;
  color: rgba(0,229,255,0.3);
  margin-bottom: auto;
}

/* Previous calculation history lines */
.calc-screen-history {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.history-item {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
}

.history-expr { color: var(--muted); }
.history-result { color: var(--accent); }

/* Active input line with blinking cursor animation */
.calc-screen-input {
  font-size: 2.5rem;
  font-weight: 700;
  color: #00ff88;
  text-align: right;
  letter-spacing: -0.02em;
  text-shadow: 0 0 20px rgba(0,255,136,0.4);
  border-top: 1px solid rgba(255,255,255,0.05);
  padding-top: 16px;
  animation: blinkCursor 1s step-end infinite;
}


/* ==========================================================================
   9. Calculator Keypad & Buttons
   ========================================================================== */
.calc-keypad {
  padding: 20px;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  align-content: start;
}

/* Base key styles */
.key {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  font-family: 'Space Mono', monospace;
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.1s;
  border: 1px solid transparent;
  user-select: none;
}

.key:active, .key.active {
  transform: scale(0.92);
}

/* Number keys — dark charcoal */
.key-num {
  background: #1c1c28;
  color: var(--text);
  border-color: rgba(255,255,255,0.08);
}
.key-num:hover { background: #252535; border-color: rgba(255,255,255,0.15); }

/* Operator keys — cyan tinted */
.key-op {
  background: rgba(0,229,255,0.1);
  color: var(--accent);
  border-color: rgba(0,229,255,0.2);
}
.key-op:hover { background: rgba(0,229,255,0.2); }

/* Function/special keys — purple tinted */
.key-fn {
  background: rgba(124,58,237,0.15);
  color: #a78bfa;
  border-color: rgba(124,58,237,0.2);
  font-size: 0.65rem;
}
.key-fn:hover { background: rgba(124,58,237,0.25); }

/* ENTER key — solid cyan CTA */
.key-eq {
  background: var(--accent);
  color: #000;
  font-weight: 700;
  border-color: transparent;
}
.key-eq:hover { box-shadow: 0 0 15px rgba(0,229,255,0.5); }

/* Wide key spans 2 columns */
.key-wide { grid-column: span 2; aspect-ratio: auto; padding: 10px; }


/* ==========================================================================
   10. Section Shared Styles
   ========================================================================== */
section {
  position: relative;
  z-index: 1;
  padding: 100px 5%;
}

/* Small labeled tag above section headings */
.section-label {
  font-family: 'Space Mono', monospace;
  font-size: 0.72rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 12px;
}

.section-label::before {
  content: '';
  display: block;
  width: 30px;
  height: 1px;
  background: var(--accent);
}

.section-title {
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: clamp(2rem, 4vw, 3.5rem);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 1rem;
}

.section-sub {
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.7;
  max-width: 560px;
}


/* ==========================================================================
   11. Features Grid
   ========================================================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5px;
  margin-top: 4rem;
  background: var(--border); /* gap acts as border lines between cards */
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}

.feature-card {
  background: var(--surface);
  padding: 40px 36px;
  transition: background 0.25s;
  position: relative;
  overflow: hidden;
}

/* Animated top border bar on hover */
.feature-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s;
}

.feature-card:hover { background: var(--surface2); }
.feature-card:hover::before { transform: scaleX(1); }

.feature-icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  background: rgba(0,229,255,0.08);
  border: 1px solid rgba(0,229,255,0.15);
}

.feature-title {
  font-family: 'Syne', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
  letter-spacing: -0.01em;
}

.feature-desc {
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.65;
}


/* ==========================================================================
   12. How It Works Section
   ========================================================================== */
.how-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
  margin-top: 4rem;
}

/* Numbered steps list */
.steps {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.step {
  display: flex;
  gap: 24px;
  padding: 32px 0;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.2s;
}

.step:first-child { padding-top: 0; }
.step:last-child { border-bottom: none; }

.step-num {
  font-family: 'Space Mono', monospace;
  font-size: 0.75rem;
  color: var(--muted);
  min-width: 32px;
  padding-top: 4px;
}

.step-content h3 {
  font-family: 'Syne', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  transition: color 0.2s;
}

.step-content p {
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

.step:hover .step-content h3 { color: var(--accent); }

/* Graph illustration panel */
.how-visual {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 40px;
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.how-visual::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at center, rgba(0,229,255,0.05) 0%, transparent 70%);
}

.graph-svg {
  width: 100%;
  height: 100%;
  max-width: 260px;
}


/* ==========================================================================
   13. Who Uses It Section
   ========================================================================== */
.who-section {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.who-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-top: 4rem;
}

.who-card {
  text-align: center;
  padding: 48px 32px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--bg);
  transition: all 0.25s;
  position: relative;
  overflow: hidden;
}

/* Animated bottom border bar on hover */
.who-card::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  transform: scaleX(0);
  transition: transform 0.3s;
}

.who-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 60px rgba(0,0,0,0.4);
}

.who-card:hover::after { transform: scaleX(1); }

.who-emoji {
  font-size: 3rem;
  margin-bottom: 1.5rem;
  display: block;
  filter: grayscale(0.3);
  transition: filter 0.25s;
}

.who-card:hover .who-emoji { filter: none; }

.who-card h3 {
  font-family: 'Syne', sans-serif;
  font-weight: 700;
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}

.who-card p {
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.65;
}


/* ==========================================================================
   14. FAQ Accordion
   ========================================================================== */
.faq-list {
  max-width: 720px;
  margin: 4rem auto 0;
}

.faq-item {
  border-bottom: 1px solid var(--border);
}

.faq-q {
  width: 100%;
  background: none;
  border: none;
  color: var(--text);
  text-align: left;
  padding: 28px 0;
  font-family: 'DM Sans', sans-serif;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  transition: color 0.2s;
}

.faq-q:hover { color: var(--accent); }

/* Plus/minus toggle icon */
.faq-icon {
  min-width: 24px; height: 24px;
  border-radius: 50%;
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: all 0.25s;
  color: var(--muted);
}

.faq-item.open .faq-icon {
  background: var(--accent);
  color: #000;
  border-color: var(--accent);
  transform: rotate(45deg); /* + becomes × */
}

/* Animated expand/collapse */
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s;
  color: var(--muted);
  font-size: 0.93rem;
  line-height: 1.7;
  padding-bottom: 0;
}

.faq-item.open .faq-a {
  max-height: 200px;
  padding-bottom: 28px;
}


/* ==========================================================================
   15. Embed Code Section
   ========================================================================== */
.embed-section { text-align: center; }

.embed-box {
  margin: 3rem auto 0;
  max-width: 700px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}

.embed-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
}

.embed-lang {
  font-family: 'Space Mono', monospace;
  font-size: 0.72rem;
  color: var(--accent);
}

.copy-btn {
  background: rgba(0,229,255,0.1);
  border: 1px solid rgba(0,229,255,0.2);
  color: var(--accent);
  padding: 6px 16px;
  border-radius: 6px;
  font-size: 0.78rem;
  font-family: 'Space Mono', monospace;
  cursor: pointer;
  transition: all 0.2s;
}

.copy-btn:hover { background: rgba(0,229,255,0.2); }
.copy-btn.copied { background: rgba(0,255,136,0.1); color: #00ff88; border-color: rgba(0,255,136,0.3); }

.embed-code {
  padding: 28px;
  font-family: 'Space Mono', monospace;
  font-size: 0.8rem;
  color: #a8b4c8;
  text-align: left;
  line-height: 1.8;
  overflow-x: auto;
  white-space: pre;
}

/* Syntax highlighting colors */
.code-tag  { color: #7c9fd4; }
.code-attr { color: #c8a96e; }
.code-val  { color: #98c379; }


/* ==========================================================================
   16. CTA (Call-to-Action) Section
   ========================================================================== */
.cta-section {
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-glow {
  position: absolute;
  width: 600px; height: 400px;
  background: radial-gradient(ellipse, rgba(0,229,255,0.08) 0%, transparent 70%);
  left: 50%; top: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.cta-inner {
  position: relative;
  background: var(--surface);
  border: 1px solid rgba(0,229,255,0.15);
  border-radius: 24px;
  padding: 80px 60px;
  max-width: 700px;
  margin: 0 auto;
  box-shadow: 0 0 0 1px rgba(0,229,255,0.05), 0 40px 80px rgba(0,0,0,0.5);
}

.cta-inner h2 {
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: clamp(2rem, 4vw, 3rem);
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1.2rem;
}

.cta-inner p {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: 2.5rem;
}


/* ==========================================================================
   17. Footer
   ========================================================================== */
footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--border);
  padding: 60px 5% 40px;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 60px;
  margin-bottom: 60px;
}

.footer-brand p {
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.7;
  margin-top: 1rem;
  max-width: 280px;
}

.footer-col h4 {
  font-family: 'Syne', sans-serif;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text);
  margin-bottom: 1.2rem;
}

.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 0.75rem; }
.footer-col a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.88rem;
  transition: color 0.2s;
}
.footer-col a:hover { color: var(--accent); }

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border);
  padding-top: 32px;
  font-size: 0.82rem;
  color: var(--muted);
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-bottom a { color: var(--muted); text-decoration: none; }
.footer-bottom a:hover { color: var(--accent); }


/* ==========================================================================
   18. Scroll Reveal Animation
   ========================================================================== */

/* Elements start hidden and slide up — JS adds .visible to trigger */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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


/* ==========================================================================
   19. Keyframe Animations
   ========================================================================== */

/* Logo dot pulse */
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%       { opacity: 0.6; transform: scale(1.3); }
}

/* Floating orbs */
@keyframes orbFloat {
  0%, 100% { transform: translate(0, 0); }
  33%       { transform: translate(30px, -20px); }
  66%       { transform: translate(-20px, 20px); }
}

/* Hero elements staggered entrance */
@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Calculator input blinking cursor */
@keyframes blinkCursor {
  0%, 100% { border-right: 2px solid #00ff88; }
  50%       { border-right: 2px solid transparent; }
}


/* ==========================================================================
   20. Responsive / Media Queries
   ========================================================================== */

/* Tablet — collapse 2-col layouts */
@media (max-width: 900px) {
  .calc-body            { grid-template-columns: 1fr; }
  .calc-keypad          { border-top: 1px solid var(--border); }
  .how-content          { grid-template-columns: 1fr; }
  .how-visual           { display: none; }
  .who-grid             { grid-template-columns: 1fr; }
  .footer-top           { grid-template-columns: 1fr 1fr; }
  .nav-links            { display: none; } /* Mobile: hide nav links */
}

/* Mobile */
@media (max-width: 600px) {
  .hero-title           { font-size: 2.8rem; }
  .hero-stats           { gap: 2rem; }
  .cta-inner            { padding: 48px 28px; }
  .footer-top           { grid-template-columns: 1fr; gap: 40px; }
}


/* ==========================================================================
   21. Custom Scrollbar
   ========================================================================== */
::-webkit-scrollbar       { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--surface2); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--muted); }