:root {
  --bg-color: #ffffff;
  --card-bg: #f8f9fa;
  --text-main: #333333;
  --text-muted: #666666;
  --accent-blue: #0066cc;
  /* Darker blue for visibility on white */
  --accent-cyan: #00ccff;
  /* Brighter accent for backgrounds */
  --accent-amber: #f59e0b;
  --border-color: #e5e7eb;
  --font-main: 'Inter', sans-serif;
  --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: var(--font-main);
  line-height: 1.6;
  overflow-x: hidden;
}

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

ul {
  list-style: none;
}

/* Typography */
h1,
h2,
h3 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
}

h1 {
  font-size: 3rem;
  letter-spacing: -0.05rem;
}

h2 {
  font-size: 2rem;
  color: var(--accent-blue);
}

p {
  margin-bottom: 1.5rem;
  color: var(--text-muted);
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 80px 0;
}

/* Header */
header {
  position: fixed;
  top: 0;
  width: 100%;
  padding: 15px 0;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-main);
}

.logo span {
  color: var(--accent-blue);
}

.nav-links {
  display: flex;
  gap: 30px;
}

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent-blue);
}

/* Hamburger Menu */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 6px;
  cursor: pointer;
  z-index: 1001;
}

.hamburger span {
  display: block;
  width: 25px;
  height: 2px;
  background-color: var(--text-main);
  transition: var(--transition);
}

/* Mobile Responsive Styles */
@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 70%;
    height: 100vh;
    background: white;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
    box-shadow: -5px 0 15px rgba(0, 0, 0, 0.1);
    transition: 0.5s ease-in-out;
    z-index: 1000;
  }

  .nav-links.active {
    right: 0;
  }

  .nav-links a {
    font-size: 1.2rem;
  }

  /* Hamburger Animation */
  .hamburger.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }

  .hamburger.active span:nth-child(2) {
    opacity: 0;
  }

  .hamburger.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }

  h1 {
    font-size: 2.2rem;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .comparison-table {
    grid-template-columns: 1fr;
  }
}


/* Hero Section */
.hero {
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(0, 204, 255, 0.1) 0%, transparent 70%);
  /* Lighter cyan */
  border-radius: 50%;
  z-index: -1;
}

.hero h1 {
  font-size: 4rem;
  margin-bottom: 1.5rem;
}

.hero p {
  font-size: 1.2rem;
  max-width: 600px;
  margin: 0 auto 2.5rem;
}

.btn {
  display: inline-block;
  padding: 12px 30px;
  border-radius: 50px;
  font-weight: 600;
  transition: var(--transition);
  border: 1px solid var(--accent-blue);
  color: var(--accent-blue);
  background: transparent;
}

.btn:hover {
  background: var(--accent-blue);
  color: var(--bg-color);
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.4);
}

/* Cards */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.card {
  background: var(--card-bg);
  padding: 40px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  transition: var(--transition);
  box-shadow: var(--shadow-card);
  /* Added shadow */
}

.card:hover {
  transform: translateY(-5px);
  border-color: var(--accent-blue);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

.card h3 {
  color: var(--accent-blue);
  margin-bottom: 1rem;
}

/* Footer */
footer {
  padding: 40px 0;
  border-top: 1px solid var(--border-color);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Animation Utilities */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Feature Specific Styles */

/* Paradigm Shift Comparison */
.comparison-table {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  margin: 40px 0;
}

.comparison-column {
  background: var(--card-bg);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.comparison-column.old {
  border-left: 4px solid var(--text-muted);
}

.comparison-column.new {
  border-left: 4px solid var(--accent-blue);
  background: #f0f9ff;
}

.comparison-column h4 {
  font-size: 1.2rem;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.comparison-list li {
  margin-bottom: 12px;
  padding-left: 20px;
  position: relative;
}

.comparison-column.old .comparison-list li::before {
  content: "×";
  position: absolute;
  left: 0;
  color: var(--text-muted);
  font-weight: bold;
}

.comparison-column.new .comparison-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--accent-blue);
  font-weight: bold;
}

/* Requirements Checklist */
.checklist {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 40px;
}

.checklist-item {
  background: white;
  padding: 20px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: flex-start;
  gap: 15px;
  transition: var(--transition);
}

.checklist-item:hover {
  border-color: var(--accent-blue);
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.checklist-number {
  background: var(--accent-blue);
  color: white;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: bold;
  flex-shrink: 0;
}

.checklist-content h4 {
  font-size: 1rem;
  margin-bottom: 5px;
  color: var(--text-main);
}

.checklist-content p {
  font-size: 0.9rem;
  margin-bottom: 0;
}

/* Solution Layer Diagram */
.layer-diagram {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: 600px;
  margin: 40px auto;
}

.layer {
  padding: 20px;
  text-align: center;
  border-radius: 8px;
  background: white;
  border: 2px solid var(--border-color);
  font-weight: bold;
  position: relative;
}

.layer.app {
  border-color: var(--accent-amber);
  background: #fffbf0;
}

.layer.os {
  border-color: var(--accent-blue);
  background: #f0f9ff;
  padding: 30px;
  font-size: 1.2rem;
}

.layer.device {
  border-color: var(--text-muted);
  background: #f3f4f6;
}

.layer::after {
  content: attr(data-label);
  display: block;
  font-size: 0.8rem;
  font-weight: normal;
  margin-top: 5px;
  color: var(--text-muted);
}