/* CSS Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Color Palette - Neutrals with High-Contrast CTAs */
  --color-bg-primary: #0f0f0f;
  --color-bg-secondary: #1a1a1a;
  --color-bg-tertiary: #252525;
  --color-text-primary: #f5f5f5;
  --color-text-secondary: #b8b8b8;
  --color-text-muted: #808080;
  --color-accent-primary: #3b82f6;
  --color-accent-secondary: #8b5cf6;
  --color-accent-gradient: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-border: #2a2a2a;

  /* Typography */
  --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2.5rem;
  --spacing-xl: 4rem;
  --spacing-xxl: 6rem;

  /* Layout */
  --container-max-width: 1000px;
  --container-padding: 2rem;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-medium: 0.4s ease;
  --transition-slow: 0.6s ease;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(59, 130, 246, 0.3);
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-primary);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

/* Scroll Progress Indicator */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 4px;
  background: var(--color-accent-gradient);
  z-index: 1000;
  transition: width 0.1s ease;
  box-shadow: 0 0 10px rgba(59, 130, 246, 0.5);
}

/* Container */
.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* Hero Section */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: radial-gradient(ellipse at center, #1a1a2e 0%, #0f0f0f 100%);
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(circle at 20% 50%, rgba(59, 130, 246, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
  animation: pulse 8s ease-in-out infinite;
  will-change: transform;
}

@keyframes pulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 0.8; }
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: var(--spacing-xl) 0;
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 4.5rem);
  font-weight: 800;
  margin-bottom: var(--spacing-md);
  background: var(--color-accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
  animation: fadeInUp 1s ease both;
}

.hero-subtitle {
  font-size: clamp(1.2rem, 2.5vw, 1.8rem);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
  animation: fadeInUp 1s ease 0.2s both;
}

.hero-cta {
  animation: fadeInUp 1s ease 0.4s both;
}

.btn-scroll {
  display: inline-block;
  padding: 1rem 2.5rem;
  background: var(--color-accent-gradient);
  color: white;
  text-decoration: none;
  border-radius: 50px;
  font-weight: 600;
  font-size: 1.1rem;
  transition: all var(--transition-medium);
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

.btn-scroll::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s;
}

.btn-scroll:hover {
  transform: translateY(-3px) scale(1.05);
  box-shadow: var(--shadow-glow);
}

.btn-scroll:hover::before {
  left: 100%;
}

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

/* Article Content */
.article-content {
  padding: var(--spacing-xxl) 0;
  background: var(--color-bg-primary);
}

.article-intro {
  font-size: 1.2rem;
  line-height: 1.8;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-lg);
  background: var(--color-bg-secondary);
  border-left: 4px solid var(--color-accent-primary);
  border-radius: 8px;
}

.article-section {
  margin-bottom: var(--spacing-xxl);
}

.article-section h2 {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  color: var(--color-text-primary);
  position: relative;
  padding-bottom: var(--spacing-sm);
}

.article-section h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 4px;
  background: var(--color-accent-gradient);
  border-radius: 2px;
}

.article-section h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  margin: var(--spacing-lg) 0 var(--spacing-md);
  color: var(--color-text-primary);
}

.article-section h4 {
  font-size: clamp(1.2rem, 2.5vw, 1.5rem);
  font-weight: 600;
  margin: var(--spacing-md) 0 var(--spacing-sm);
  color: var(--color-accent-primary);
}

.article-section p {
  margin-bottom: var(--spacing-md);
  line-height: 1.8;
  color: var(--color-text-secondary);
}

.article-section ul,
.article-section ol {
  margin: var(--spacing-md) 0;
  padding-left: var(--spacing-lg);
}

.article-section li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.7;
  color: var(--color-text-secondary);
}

.article-section li::marker {
  color: var(--color-accent-primary);
}

/* Checklist */
.checklist {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
  margin: var(--spacing-lg) 0;
}

.checklist-item {
  background: var(--color-bg-secondary);
  padding: var(--spacing-lg);
  border-radius: 12px;
  border: 1px solid var(--color-border);
  transition: all var(--transition-medium);
  position: relative;
  overflow: hidden;
}

.checklist-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--color-accent-gradient);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-medium);
}

.checklist-item:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-accent-primary);
}

.checklist-item:hover::before {
  transform: scaleX(1);
}

.checklist-item h3 {
  font-size: 1.3rem;
  margin-top: 0;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-primary);
}

.checklist-item ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.checklist-item li {
  padding-left: 1.5rem;
  position: relative;
  margin-bottom: var(--spacing-xs);
}

.checklist-item li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-success);
  font-weight: bold;
}

/* Pattern Cards */
.pattern-card {
  background: var(--color-bg-secondary);
  padding: var(--spacing-lg);
  border-radius: 12px;
  margin-bottom: var(--spacing-lg);
  border: 1px solid var(--color-border);
  transition: all var(--transition-medium);
}

.pattern-card:hover {
  transform: translateX(10px);
  border-color: var(--color-accent-secondary);
  box-shadow: var(--shadow-md);
}

.pattern-card h3 {
  margin-top: 0;
  color: var(--color-accent-secondary);
}

.pattern-card pre {
  background: var(--color-bg-tertiary);
  padding: var(--spacing-md);
  border-radius: 8px;
  overflow-x: auto;
  margin: var(--spacing-md) 0;
  border-left: 3px solid var(--color-accent-primary);
}

.pattern-card code {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--color-text-primary);
  line-height: 1.6;
}

/* Failure Modes */
.failure-mode {
  background: var(--color-bg-secondary);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
  border-radius: 8px;
  border-left: 4px solid var(--color-warning);
  transition: all var(--transition-medium);
}

.failure-mode:hover {
  background: var(--color-bg-tertiary);
  transform: translateX(5px);
}

.failure-mode h4 {
  margin-top: 0;
  color: var(--color-warning);
}

/* Metric Cards */
.metric-card {
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg-tertiary) 100%);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
  border-radius: 8px;
  border: 1px solid var(--color-border);
  transition: all var(--transition-medium);
  position: relative;
  overflow: hidden;
}

.metric-card::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 100px;
  height: 100px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, transparent 70%);
  transform: translate(30%, -30%);
}

.metric-card:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow-md);
  border-color: var(--color-accent-primary);
}

.metric-card h4 {
  margin-top: 0;
  color: var(--color-accent-primary);
}

/* Mistake Cards */
.mistake-card {
  background: var(--color-bg-secondary);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  border-radius: 12px;
  border: 1px solid var(--color-border);
  transition: all var(--transition-medium);
  position: relative;
}

.mistake-card::before {
  content: '!';
  position: absolute;
  top: var(--spacing-md);
  right: var(--spacing-md);
  width: 40px;
  height: 40px;
  background: var(--color-warning);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 1.5rem;
  color: var(--color-bg-primary);
  opacity: 0.2;
  transition: all var(--transition-medium);
}

.mistake-card:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow-md);
  border-color: var(--color-warning);
}

.mistake-card:hover::before {
  opacity: 1;
  transform: rotate(12deg);
}

.mistake-card h3 {
  margin-top: 0;
  color: var(--color-text-primary);
}

.mistake-card strong {
  color: var(--color-success);
}

/* Numbered List */
.numbered-list {
  counter-reset: step-counter;
  list-style: none;
  padding: 0;
}

.numbered-list li {
  counter-increment: step-counter;
  position: relative;
  padding-left: 4rem;
  margin-bottom: var(--spacing-lg);
}

.numbered-list li::before {
  content: counter(step-counter);
  position: absolute;
  left: 0;
  top: 0;
  width: 2.5rem;
  height: 2.5rem;
  background: var(--color-accent-gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: white;
  font-size: 1.2rem;
}

/* CTA Section */
.cta-section {
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg-tertiary) 100%);
  padding: var(--spacing-xxl) 0;
  margin-top: var(--spacing-xxl);
  border-top: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.05) 0%, transparent 70%);
  animation: rotate 20s linear infinite;
}

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

.cta-content {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--spacing-xl);
  align-items: center;
  position: relative;
  z-index: 1;
}

.cta-image {
  text-align: center;
}

.profile-image {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  border: 4px solid var(--color-accent-primary);
  box-shadow: var(--shadow-glow);
  transition: all var(--transition-medium);
  object-fit: cover;
}

.profile-image:hover {
  transform: scale(1.1) rotate(5deg);
  box-shadow: 0 0 40px rgba(59, 130, 246, 0.6);
}

.cta-text h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: var(--spacing-sm);
  background: var(--color-accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.cta-subtitle {
  font-size: 1.2rem;
  color: var(--color-accent-primary);
  margin-bottom: var(--spacing-md);
  font-weight: 600;
}

.cta-text p {
  margin-bottom: var(--spacing-md);
  line-height: 1.7;
  color: var(--color-text-secondary);
}

.cta-button {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 1rem 2rem;
  background: var(--color-accent-gradient);
  color: white;
  text-decoration: none;
  border-radius: 50px;
  font-weight: 600;
  font-size: 1.1rem;
  margin-top: var(--spacing-md);
  transition: all var(--transition-medium);
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

.cta-button::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width 0.6s, height 0.6s;
}

.cta-button:hover {
  transform: translateY(-3px) scale(1.05);
  box-shadow: var(--shadow-glow);
}

.cta-button:hover::before {
  width: 300px;
  height: 300px;
}

.cta-button svg {
  transition: transform var(--transition-fast);
  position: relative;
  z-index: 1;
}

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

.cta-button span {
  position: relative;
  z-index: 1;
}

/* Footer */
.footer {
  background: var(--color-bg-primary);
  padding: var(--spacing-lg) 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-text-muted);
}

/* Reveal Animations */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --container-padding: 1.5rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
  }

  .hero {
    min-height: 80vh;
  }

  .hero-title {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1.1rem;
  }

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

  .cta-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .profile-image {
    width: 150px;
    height: 150px;
  }

  .numbered-list li {
    padding-left: 3rem;
  }

  .numbered-list li::before {
    width: 2rem;
    height: 2rem;
    font-size: 1rem;
  }
}

@media (max-width: 480px) {
  .article-intro {
    font-size: 1rem;
    padding: var(--spacing-md);
  }

  .btn-scroll {
    padding: 0.8rem 2rem;
    font-size: 1rem;
  }

  .cta-button {
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
  }
}

/* Print Styles */
@media print {
  body {
    background: white;
    color: black;
  }

  .scroll-progress,
  .hero-background,
  .cta-button,
  .btn-scroll,
  .footer {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: 2rem 0;
  }

  .article-section {
    page-break-inside: avoid;
  }

  .cta-section {
    page-break-before: always;
  }
}

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

  html {
    scroll-behavior: auto;
  }
}

/* Focus Styles for Keyboard Navigation */
a:focus,
button:focus {
  outline: 2px solid var(--color-accent-primary);
  outline-offset: 4px;
}