/* ============================================
   RTFM — Design System & Shared Styles
   ============================================ */

/* --- Design Tokens --- */
:root {
  --bg-body: #08080e;
  --bg-section: #0c0c15;
  --bg-section-alt: #0f0f1a;
  --bg-card: #14142280;
  --bg-card-hover: #1c1c30;
  --bg-nav: rgba(8, 8, 14, 0.82);
  --bg-input: #12121e;

  --text-primary: #ededf2;
  --text-secondary: #9494ad;
  --text-muted: #5c5c72;

  --accent: #dc2626;
  --accent-light: #ef4444;
  --accent-dark: #b91c1c;
  --accent-glow: rgba(220, 38, 38, 0.12);
  --accent-glow-strong: rgba(220, 38, 38, 0.25);

  --youtube-red: #ff0000;

  --border: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);
  --border-accent: rgba(220, 38, 38, 0.3);

  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', 'Cascadia Code', 'Segoe UI Mono', Menlo, monospace;

  --container: 1140px;
  --container-narrow: 760px;
  --section-py: clamp(4rem, 8vw, 7rem);
  --radius: 14px;
  --radius-sm: 8px;
  --transition: 0.25s ease;
}

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
button, input, textarea { font: inherit; }
ul, ol { list-style: none; }

/* --- Layout --- */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2rem);
}
.container--narrow { max-width: var(--container-narrow); }
.section {
  padding: var(--section-py) 0;
}
.section--alt { background: var(--bg-section-alt); }

/* --- Typography --- */
h1, h2, h3, h4 { line-height: 1.15; font-weight: 700; }
h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); letter-spacing: -0.03em; }
h2 { font-size: clamp(1.75rem, 4vw, 2.75rem); letter-spacing: -0.02em; }
h3 { font-size: clamp(1.2rem, 2.5vw, 1.5rem); }
.section-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}
.section-title { margin-bottom: 1rem; }
.section-desc {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 600px;
  line-height: 1.7;
}
.text-center { text-align: center; }
.text-center .section-desc { margin-inline: auto; }
.accent-text { color: var(--accent-light); }
.gradient-text {
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 1rem 0;
  transition: background var(--transition), box-shadow var(--transition), padding var(--transition);
}
.nav.scrolled {
  background: var(--bg-nav);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 var(--border);
  padding: 0.65rem 0;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
.nav-logo .logo-accent { color: var(--accent); }
.nav-logo img {
  height: 28px;
  width: auto;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}
.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition);
  position: relative;
}
.nav-links a:hover,
.nav-links a.active { color: var(--text-primary); }
.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0; right: 0;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: 0.5rem;
}
.nav-toggle svg { display: block; }

/* --- Mobile Nav --- */
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: fixed;
    top: 0; right: 0; bottom: 0;
    width: 280px;
    background: #10101c;
    flex-direction: column;
    justify-content: center;
    gap: 2rem;
    transform: translateX(100%);
    transition: transform 0.35s ease;
    border-left: 1px solid var(--border);
  }
  .nav-links.open { transform: translateX(0); }
  .nav-links a { font-size: 1.15rem; }
  .nav-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 99;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
  }
  .nav-overlay.visible { opacity: 1; pointer-events: all; }
}

/* --- Hero --- */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: 5rem;
}
.hero--short { min-height: 50vh; }
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(220,38,38,0.08) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 80% 100%, rgba(30,30,80,0.15) 0%, transparent 60%),
    var(--bg-body);
  z-index: 0;
}
.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 24px 24px;
}
.hero .container { position: relative; z-index: 1; }
.hero-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}
.hero-image {
  display: flex;
  justify-content: center;
}
.hero-image img {
  max-width: 100%;
  height: auto;
  filter: drop-shadow(0 20px 40px rgba(0,0,0,0.4));
}
@media (max-width: 900px) {
  .hero-layout {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .hero-image { order: -1; }
  .hero-image img { max-width: 80%; }
}
.hero-content { max-width: 700px; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background: var(--accent-glow);
  border: 1px solid var(--border-accent);
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-light);
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.hero-badge .dot {
  width: 6px; height: 6px;
  background: var(--accent);
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}
.hero h1 { margin-bottom: 1rem; }
.hero-sub {
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 560px;
  margin-bottom: 2.5rem;
}
.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 0 20px var(--accent-glow-strong);
}
.btn-primary:hover {
  background: var(--accent-light);
  box-shadow: 0 0 30px var(--accent-glow-strong);
  transform: translateY(-1px);
}
.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-hover);
}
.btn-secondary:hover {
  border-color: var(--text-muted);
  background: rgba(255,255,255,0.03);
}
.btn-youtube {
  background: var(--youtube-red);
  color: #fff;
  font-size: 1.1rem;
  padding: 1rem 2.25rem;
  border-radius: var(--radius);
  box-shadow: 0 0 30px rgba(255,0,0,0.2);
}
.btn-youtube:hover {
  box-shadow: 0 0 40px rgba(255,0,0,0.3);
  transform: translateY(-2px);
}
.btn-youtube svg { flex-shrink: 0; }

/* --- Cards --- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: all var(--transition);
}
.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  transform: translateY(-2px);
}
.card-grid {
  display: grid;
  gap: 1.5rem;
}
.card-grid--2 { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.card-grid--3 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* --- Stats Bar --- */
.stats-bar {
  display: flex;
  justify-content: center;
  gap: clamp(2rem, 6vw, 4rem);
  flex-wrap: wrap;
  padding: 2.5rem 0;
}
.stat {
  text-align: center;
}
.stat-value {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  color: var(--accent-light);
  line-height: 1;
}
.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 500;
}

/* --- Book Cards --- */
.book-card {
  text-align: center;
  padding: 2.5rem 1.5rem;
}
.book-cover {
  width: 160px;
  height: auto;
  margin: 0 auto 1.5rem;
  border-radius: 4px 10px 10px 4px;
  box-shadow: 6px 6px 24px rgba(0,0,0,0.4);
  transition: transform var(--transition), box-shadow var(--transition);
}
.book-card:hover .book-cover {
  transform: translateY(-4px) scale(1.02);
  box-shadow: 8px 8px 32px rgba(0,0,0,0.5);
}
.book-card h3 { margin-bottom: 0.5rem; }
.book-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
}
.book-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--accent-light);
  font-weight: 600;
  font-size: 0.9rem;
  transition: gap var(--transition);
}
.book-link:hover { gap: 0.7rem; }

/* --- Testimonials --- */
.testimonial {
  padding: 2rem;
  position: relative;
}
.testimonial::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--accent);
  border-radius: 3px;
}
.testimonial-quote {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 1.25rem;
  font-style: italic;
}
.testimonial-author {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
}

/* --- Author Cards --- */
.author-card {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
  padding: 2.5rem;
}
.author-avatar {
  width: 100px; height: 100px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
  border: 2px solid var(--border-hover);
}
.author-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.author-info h3 { margin-bottom: 0.5rem; }
.author-info .author-role {
  color: var(--accent-light);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
}
.author-info p {
  color: var(--text-secondary);
  line-height: 1.75;
}
@media (max-width: 640px) {
  .author-card { flex-direction: column; align-items: center; text-align: center; }
}

/* --- Video Library Curriculum --- */
.curriculum-section {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
  overflow: hidden;
  background: var(--bg-card);
}
.curriculum-section summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  color: var(--text-primary);
  transition: background var(--transition);
  list-style: none;
}
.curriculum-section summary::-webkit-details-marker { display: none; }
.curriculum-section summary::after {
  content: '';
  width: 8px; height: 8px;
  border-right: 2px solid var(--text-muted);
  border-bottom: 2px solid var(--text-muted);
  transform: rotate(-45deg);
  transition: transform var(--transition);
  flex-shrink: 0;
  margin-left: 1rem;
}
.curriculum-section[open] summary::after { transform: rotate(45deg); }
.curriculum-section summary:hover { background: rgba(255,255,255,0.02); }
.curriculum-section .section-num {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  margin-right: 0.75rem;
  min-width: 1.5rem;
}
.curriculum-videos {
  padding: 0 1.5rem 1.25rem;
  border-top: 1px solid var(--border);
}
.video-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 0;
  border-bottom: 1px solid rgba(255,255,255,0.03);
  font-size: 0.9rem;
}
.video-item:last-child { border-bottom: none; }
.video-item-name { color: var(--text-secondary); }
.video-item-scenario { color: var(--accent-light); font-weight: 500; }
.video-item-duration {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  flex-shrink: 0;
  margin-left: 1rem;
}

/* --- Endorsement / Feature Quote --- */
.endorsement {
  border-left: 3px solid var(--accent);
  padding: 2rem 2.5rem;
  background: var(--bg-card);
  border-radius: 0 var(--radius) var(--radius) 0;
}
.endorsement blockquote {
  font-size: 1.15rem;
  line-height: 1.75;
  color: var(--text-secondary);
  font-style: italic;
  margin-bottom: 1rem;
}
.endorsement cite {
  color: var(--text-primary);
  font-weight: 600;
  font-style: normal;
  font-size: 0.95rem;
}

/* --- YouTube CTA Block --- */
.yt-cta {
  text-align: center;
  padding: 3rem 2rem;
  background: radial-gradient(ellipse at center, rgba(255,0,0,0.06) 0%, transparent 70%);
  border: 1px solid rgba(255,0,0,0.1);
  border-radius: var(--radius);
}
.yt-cta h2 { margin-bottom: 0.75rem; }
.yt-cta p {
  color: var(--text-secondary);
  margin-bottom: 2rem;
  font-size: 1.05rem;
}

/* --- Narrative Block --- */
.narrative {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem;
  max-width: 760px;
  margin: 0 auto;
}
.narrative h3 { margin-bottom: 1rem; }
.narrative p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1rem;
}
.narrative p:last-child { margin-bottom: 0; }

/* --- Forms --- */
.form-group {
  margin-bottom: 1.25rem;
}
.form-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.form-input,
.form-textarea {
  width: 100%;
  padding: 0.85rem 1rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.95rem;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.form-textarea {
  min-height: 140px;
  resize: vertical;
}

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--border);
  padding: 3rem 0;
  margin-top: var(--section-py);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}
.footer-copy {
  color: var(--text-muted);
  font-size: 0.85rem;
}
.footer-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}
.footer-links a {
  color: var(--text-muted);
  font-size: 0.85rem;
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--text-primary); }
.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition);
}
.social-link:hover { color: var(--text-primary); }
.social-link svg { width: 18px; height: 18px; }

/* --- Utility --- */
.mt-0 { margin-top: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-6 { margin-bottom: 3rem; }
.gap-2 { gap: 1rem; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }

/* --- Scroll Reveal --- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Responsive --- */
@media (max-width: 640px) {
  .hero { min-height: 80vh; }
  .hero--short { min-height: 40vh; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; justify-content: center; }
  .stats-bar { gap: 1.5rem; }
  .footer-inner { flex-direction: column; text-align: center; }
}