:root {
  /* Light mode */
  --bg-primary: #EEEEEE;
  --bg-secondary: #e0e0e0;
  --bg-code: #dcdcdc;
  --bg-accent: #e6f5f6;
  --bg-highlight: #f5fcfd;
  --text-primary: #222831;
  --text-secondary: #393e46;
  --text-muted: #5c636e;
  --border-light: #d1d1d1;
  --border-medium: #c0c0c0;
  --accent-color: #00ADB5;
  --accent-hover: #00c2cc;
  --accent-dark: #008f96;
  --shadow-light: rgba(34, 40, 49, 0.05);
  --shadow-medium: rgba(34, 40, 49, 0.1);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-primary: #222831;
  --bg-secondary: #393e46;
  --bg-code: #2d3239;
  --bg-accent: #1e3538;
  --bg-highlight: #1a2e30;
  --text-primary: #EEEEEE;
  --text-secondary: #d4d4d4;
  --text-muted: #a0a0a0;
  --border-light: #444b54;
  --border-medium: #505662;
  --accent-color: #00ADB5;
  --accent-hover: #00c2cc;
  --accent-dark: #008f96;
  --shadow-light: rgba(238, 238, 238, 0.05);
  --shadow-medium: rgba(238, 238, 238, 0.1);
}

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

html {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  scroll-behavior: smooth;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: var(--transition);
}

body {
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: var(--transition);
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-light);
  backdrop-filter: blur(10px);
  padding: 1rem 0;
  margin-bottom: 2rem;
}

.header-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.back-link, .docs-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  text-decoration: none;
  border-radius: 50px;
  font-weight: 500;
  font-size: 0.9rem;
  transition: var(--transition);
  box-shadow: 0 2px 8px var(--shadow-medium);
}

.back-link {
  background: var(--accent-color);
  color: var(--bg-primary);
}

.docs-link {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 2px solid var(--border-medium);
}

.back-link:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px var(--shadow-medium);
}

.docs-link:hover {
  border-color: var(--accent-color);
  background: var(--bg-highlight);
}

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: 2px solid var(--border-medium);
  border-radius: 50px;
  padding: 0.5rem;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
}

.theme-toggle:hover {
  border-color: var(--accent-color);
  background: var(--bg-secondary);
}

.theme-icon {
  width: 20px;
  height: 20px;
  fill: var(--text-primary);
  transition: var(--transition);
}

/* Main Content */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem 4rem;
}

/* Typography */
h1 {
  font-size: 3rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-dark) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: 1.75rem;
  font-weight: 600;
  margin: 3rem 0 1.5rem;
  color: var(--text-primary);
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--accent-color);
  display: inline-block;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2rem 0 1rem;
  color: var(--text-primary);
}

h4 {
  font-size: 1.1rem;
  font-weight: 500;
  margin: 1.5rem 0 0.75rem;
  color: var(--text-secondary);
}

p {
  margin-bottom: 1.25rem;
  color: var(--text-secondary);
}

/* Hero Section */
.hero {
  text-align: center;
  margin-bottom: 4rem;
  padding: 2rem 0;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  font-weight: 300;
}

/* Concept Boxes */
.concept-box {
  background: var(--bg-secondary);
  border: 2px solid var(--border-light);
  border-radius: 16px;
  padding: 2rem;
  margin: 2rem 0;
  position: relative;
  overflow: hidden;
}

.concept-box::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--accent-color);
}

.concept-box h3 {
  margin-top: 0;
  color: var(--accent-dark);
}

.highlight-box {
  background: var(--bg-highlight);
  border: 2px solid var(--accent-color);
  border-radius: 12px;
  padding: 1.5rem;
  margin: 2rem 0;
}

.highlight-box .icon {
  font-size: 2rem;
  margin-bottom: 1rem;
  display: block;
}

/* Visual Flow */
.visual-flow {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin: 2rem 0;
}

.flow-step {
  background: var(--bg-secondary);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
  border: 2px solid var(--border-light);
  transition: var(--transition);
  position: relative;
}

.flow-step:hover {
  border-color: var(--accent-color);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--shadow-medium);
}

.flow-step-number {
  background: var(--accent-color);
  color: var(--bg-primary);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  margin: 0 auto 1rem;
}

.flow-step h4 {
  margin: 0 0 0.5rem;
  color: var(--text-primary);
}

.flow-step p {
  margin: 0;
  font-size: 0.9rem;
}

/* Code Examples */
pre, code {
  font-family: 'JetBrains Mono', 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
}

code {
  background: var(--bg-code);
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
  font-size: 0.9em;
  color: var(--text-primary);
  border: 1px solid var(--border-light);
}

pre {
  background: var(--bg-code);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 1.5rem;
  overflow-x: auto;
  margin: 1.5rem 0;
  line-height: 1.6;
  position: relative;
}

pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--text-primary);
  font-size: 0.85rem;
}

/* Lists */
ul, ol {
  margin: 1rem 0 1.5rem 1.5rem;
  color: var(--text-secondary);
}

li {
  margin-bottom: 0.5rem;
}

li strong {
  color: var(--text-primary);
}

/* Links */
a {
  color: var(--accent-dark);
  text-decoration: none;
  transition: var(--transition);
  border-bottom: 1px solid transparent;
}

a:hover {
  color: var(--accent-color);
  border-bottom-color: var(--accent-color);
}

/* Mermaid Diagrams */
.mermaid {
  background: var(--bg-secondary);
  border-radius: 12px;
  padding: 1.5rem;
  margin: 2rem 0;
  border: 1px solid var(--border-light);
}

/* Interactive Demo Placeholder */
.demo-placeholder {
  background: var(--bg-secondary);
  border: 2px dashed var(--border-medium);
  border-radius: 12px;
  padding: 3rem 2rem;
  text-align: center;
  margin: 2rem 0;
  color: var(--text-muted);
}

/* Dividers */
hr {
  border: none;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--border-medium), transparent);
  margin: 3rem 0;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.container > * {
  animation: fadeInUp 0.6s ease-out;
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 1rem 2rem;
  }

  .header-content {
    padding: 0 1rem;
    flex-direction: column;
    gap: 1rem;
  }

  .nav-links {
    order: -1;
  }

  h1 {
    font-size: 2.25rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  .visual-flow {
    grid-template-columns: 1fr;
  }

  .concept-box, .highlight-box {
    padding: 1.5rem;
  }
}