:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --accent-green: #39d353;
  --accent-cyan: #58a6ff;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --border: #30363d;
  --danger: #f85149;
  --radius: 8px;
  --max-width: 960px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent-cyan); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== NAV ===== */
.nav {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.nav-brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent-green);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-brand svg { width: 24px; height: 24px; }
.nav-links { display: flex; gap: 1.25rem; flex-wrap: wrap; }
.nav-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  transition: color 0.15s;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--text-primary);
  text-decoration: none;
}

/* ===== LAYOUT ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* ===== HERO ===== */
.hero {
  text-align: center;
  padding: 4rem 1.5rem;
}
.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
  background: linear-gradient(135deg, var(--accent-green), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero .tagline {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
}

/* ===== DIAGRAM ===== */
.diagram-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin: 2rem auto;
  max-width: 700px;
  overflow-x: auto;
}
.diagram-container svg {
  width: 100%;
  height: auto;
}

/* ===== FEATURES GRID ===== */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}
.feature-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: border-color 0.2s;
}
.feature-card:hover { border-color: var(--accent-green); }
.feature-card h3 {
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.feature-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ===== PLATFORM CARDS ===== */
.platforms {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}
.platform-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
  transition: border-color 0.2s, transform 0.2s;
  display: block;
  color: var(--text-primary);
}
.platform-card:hover {
  border-color: var(--accent-cyan);
  transform: translateY(-2px);
  text-decoration: none;
}
.platform-card svg {
  width: 48px;
  height: 48px;
  margin-bottom: 0.75rem;
  fill: var(--text-secondary);
}
.platform-card:hover svg { fill: var(--accent-cyan); }
.platform-card span {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
}

/* ===== SECTION ===== */
.section { margin: 3rem 0; }
.section h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

/* ===== CODE BLOCKS ===== */
.code-block {
  position: relative;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 1rem 0;
  overflow: hidden;
}
.code-block pre {
  padding: 1rem 1.25rem;
  overflow-x: auto;
  font-family: 'SF Mono', 'Fira Code', 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--text-primary);
}
.code-block .copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.75rem;
  transition: color 0.15s, border-color 0.15s;
}
.code-block .copy-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-green);
}
.code-block .copy-btn.copied {
  color: var(--accent-green);
  border-color: var(--accent-green);
}

code {
  font-family: 'SF Mono', 'Fira Code', 'JetBrains Mono', monospace;
  font-size: 0.85em;
  background: var(--bg-tertiary);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

/* ===== BREADCRUMB ===== */
.breadcrumb {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}
.breadcrumb a { color: var(--accent-cyan); }

/* ===== STEPS ===== */
.steps { counter-reset: step; }
.step {
  counter-increment: step;
  margin: 1.5rem 0;
  padding-left: 2.5rem;
  position: relative;
}
.step::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 1.75rem;
  height: 1.75rem;
  background: var(--accent-green);
  color: var(--bg-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
}
.step h3 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
}
.step p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ===== CALLOUT ===== */
.callout {
  border-left: 3px solid var(--accent-cyan);
  background: var(--bg-secondary);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1rem 0;
  font-size: 0.9rem;
}
.callout.warning {
  border-left-color: #d29922;
}
.callout.danger {
  border-left-color: var(--danger);
}
.callout strong {
  display: block;
  margin-bottom: 0.25rem;
}

/* ===== FIGURE ===== */
.screenshot {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin: 1rem 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-style: italic;
}

/* ===== FOOTER ===== */
.footer {
  border-top: 1px solid var(--border);
  padding: 2rem 1.5rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-top: 4rem;
}
.footer a { color: var(--accent-cyan); }

/* ===== HOW IT WORKS ===== */
.how-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}
.how-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.how-card .number {
  display: inline-block;
  width: 2rem;
  height: 2rem;
  background: var(--accent-green);
  color: var(--bg-primary);
  border-radius: 50%;
  text-align: center;
  line-height: 2rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}
.how-card h3 { font-size: 1rem; margin-bottom: 0.5rem; }
.how-card p { font-size: 0.85rem; color: var(--text-secondary); }

/* ===== RESPONSIVE ===== */
@media (max-width: 640px) {
  .hero h1 { font-size: 1.75rem; }
  .hero .tagline { font-size: 1rem; }
  .nav-links { gap: 0.75rem; }
  .nav-links a { font-size: 0.8rem; }
}