/* VibeCodingTutor - Main Stylesheet
 * Served via jsDelivr Multi-CDN: https://www.jsdelivr.com/
 * Combines Cloudflare, Fastly, and BunnyCDN for global performance */

:root {
  --bg: #0f172a;
  --bg-alt: #1e293b;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  --code-bg: #1e293b;
  --border: #334155;
  --footer: #64748b;
  --shadow: rgba(0, 0, 0, 0.3);
  --radius: 0.5rem;
  --transition: 0.15s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
    Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem;
}

/* ── Header & Navigation ──────────────────────────────────── */

header {
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 100;
  backdrop-filter: blur(8px);
}

nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
}

nav a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition);
  padding: 0.25rem 0;
  position: relative;
}

nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: width var(--transition);
}

nav a:hover::after,
nav a:focus::after {
  width: 100%;
}

nav a:hover,
nav a:focus {
  color: var(--primary-hover);
  text-decoration: none;
}

/* ── Main Content ─────────────────────────────────────────── */

main {
  content-visibility: auto;
  contain-intrinsic-size: 0 500px;
  min-height: 60vh;
}

h1 {
  font-size: 2rem;
  margin-bottom: 0.75rem;
  line-height: 1.2;
  color: var(--text);
}

h2 {
  font-size: 1.5rem;
  margin: 1.5rem 0 0.75rem;
  line-height: 1.3;
  color: var(--text);
}

h3 {
  font-size: 1.125rem;
  margin: 1.25rem 0 0.5rem;
  color: var(--text);
}

p {
  margin-bottom: 0.75rem;
}

a {
  color: var(--primary);
  transition: color var(--transition);
}

a:hover {
  color: var(--primary-hover);
}

/* ── Code ─────────────────────────────────────────────────── */

pre {
  background: var(--code-bg);
  padding: 1rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 1rem 0;
  font-size: 0.875rem;
  border: 1px solid var(--border);
}

code {
  font-family: 'Fira Code', 'Cascadia Code', Consolas, 'Courier New', monospace;
  font-size: 0.875rem;
  background: var(--code-bg);
  padding: 0.125rem 0.375rem;
  border-radius: 0.25rem;
}

pre code {
  background: none;
  padding: 0;
}

/* ── Tables ───────────────────────────────────────────────── */

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
}

th, td {
  padding: 0.75rem;
  border: 1px solid var(--border);
  text-align: left;
}

th {
  background: var(--code-bg);
  font-weight: 600;
}

/* ── Hero ─────────────────────────────────────────────────── */

.hero {
  text-align: center;
  padding: 2rem 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

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

.hero p {
  font-size: 1.125rem;
  color: var(--text-muted);
}

/* ── Buttons ──────────────────────────────────────────────── */

.btn {
  display: inline-block;
  padding: 0.625rem 1.25rem;
  background: var(--primary);
  color: #fff;
  text-decoration: none;
  border-radius: var(--radius);
  font-weight: 600;
  margin: 0.5rem;
  transition: background var(--transition), transform var(--transition);
  border: none;
  cursor: pointer;
}

.btn:hover {
  background: var(--primary-hover);
  color: #fff;
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--primary);
  color: var(--primary);
}

.btn-outline:hover {
  background: var(--primary);
  color: #fff;
}

/* ── Features Grid ────────────────────────────────────────── */

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.feature {
  padding: 1.25rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color var(--transition), box-shadow var(--transition);
  background: var(--bg);
}

.feature:hover {
  border-color: var(--primary);
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.15);
}

.feature h3 {
  margin-top: 0;
}

/* ── Cards ────────────────────────────────────────────────── */

.card {
  padding: 1.25rem;
  border-left: 4px solid var(--primary);
  background: var(--code-bg);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.card h4 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.card p {
  margin-bottom: 0.5rem;
}

.grid {
  display: grid;
  gap: 1rem;
  margin: 1.5rem 0;
}

/* ── Lists ────────────────────────────────────────────────── */

ul, ol {
  margin-left: 1.5rem;
  margin-bottom: 0.75rem;
}

li {
  margin-bottom: 0.375rem;
}

blockquote {
  border-left: 4px solid var(--primary);
  padding-left: 1rem;
  margin: 1rem 0;
  color: var(--text-muted);
}

/* ── Footer ───────────────────────────────────────────────── */

footer {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--footer);
  font-size: 0.875rem;
}

footer a {
  color: var(--text-muted);
}

footer a:hover {
  color: var(--primary);
}

/* ── jsDelivr Badge ───────────────────────────────────────── */

.jsdelivr-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.375rem 0.75rem;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: border-color var(--transition);
}

.jsdelivr-badge:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.jsdelivr-badge img {
  height: 16px;
  width: auto;
}

/* ── Accessibility ────────────────────────────────────────── */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 1000;
}

.skip-link:focus {
  top: 0;
}

/* ── Responsive ───────────────────────────────────────────── */

@media (max-width: 600px) {
  .container {
    padding: 1rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  nav {
    gap: 0.75rem;
  }

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