/* ============================================
   FlipStack — Dark editorial, amber accent
   ============================================ */

:root {
  --bg: #0D0D0D;
  --bg2: #111111;
  --bg3: #1A1A1A;
  --fg: #F0EDE6;
  --fg2: #8A8680;
  --accent: #F5A623;
  --accent-dim: rgba(245, 166, 35, 0.15);
  --border: rgba(240, 237, 230, 0.08);
  --font-display: 'Syne', sans-serif;
  --font-body: 'DM Sans', sans-serif;
}

/* RESET */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; }
body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* NAV */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 40px;
  background: rgba(13,13,13,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex;
  align-items: baseline;
  gap: 16px;
  max-width: 1200px;
  margin: 0 auto;
}
.wordmark {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: 0.05em;
  color: var(--fg);
}
.tagline {
  font-size: 0.75rem;
  color: var(--fg2);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.nav-link {
  font-size: 0.8rem;
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  letter-spacing: 0.04em;
  transition: opacity 0.15s;
}
.nav-link:hover { opacity: 0.7; }

/* HERO */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 120px 40px 80px;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.stack-visual {
  position: absolute;
  right: -60px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 14px;
  opacity: 0.12;
}
.crate {
  width: 320px;
  height: 48px;
  border: 1.5px solid var(--accent);
  border-radius: 3px;
  background: transparent;
}
.c1 { width: 200px; }
.c2 { width: 240px; }
.c3 { width: 280px; }
.c4 { width: 260px; }
.c5 { width: 300px; }
.c6 { width: 220px; }
.glow-orb {
  position: absolute;
  right: 100px;
  top: 50%;
  transform: translateY(-50%);
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(245,166,35,0.12) 0%, transparent 70%);
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 760px;
}
.hero-img-wrap {
  position: absolute;
  right: 40px;
  top: 50%;
  transform: translateY(-50%);
  width: 460px;
  height: 320px;
  overflow: hidden;
  border-radius: 8px;
  opacity: 0.18;
  z-index: 1;
}
.hero-img { width: 100%; height: 100%; object-fit: cover; }
.kicker {
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 16px;
}
.headline {
  font-family: var(--font-display);
  font-size: clamp(3.5rem, 8vw, 7rem);
  font-weight: 800;
  line-height: 0.9;
  letter-spacing: -0.02em;
  color: var(--fg);
  margin-bottom: 6px;
}
.headline-sub {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3.5vw, 2.5rem);
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.01em;
  margin-bottom: 24px;
}
.lede {
  font-size: 1.1rem;
  line-height: 1.65;
  color: var(--fg2);
  max-width: 560px;
  margin-bottom: 40px;
}
.hero-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.btn-primary {
  display: inline-block;
  background: var(--accent);
  color: #0D0D0D;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 14px 28px;
  border-radius: 4px;
  text-decoration: none;
  transition: opacity 0.15s, transform 0.15s;
  letter-spacing: 0.02em;
  border: none;
  cursor: pointer;
}
.btn-primary:hover { opacity: 0.85; transform: translateY(-1px); }
.btn-primary.btn-large { font-size: 1rem; padding: 18px 36px; border-radius: 5px; }
.btn-ghost {
  display: inline-block;
  color: var(--fg2);
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  padding: 14px 20px;
  border: 1px solid var(--border);
  border-radius: 4px;
  text-decoration: none;
  transition: color 0.15s, border-color 0.15s;
}
.btn-ghost:hover { color: var(--fg); border-color: rgba(240,237,230,0.28); }

/* SECTION SHARED */
.section-label {
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 16px;
}
.section-headline {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3.25rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--fg);
  max-width: 640px;
}

/* HOW */
.how {
  padding: 100px 40px;
  border-top: 1px solid var(--border);
}
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  margin-top: 56px;
  background: var(--border);
  border: 1px solid var(--border);
}
.step {
  background: var(--bg);
  padding: 40px 36px;
  position: relative;
}
.step-num {
  font-family: var(--font-display);
  font-size: 0.7rem;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: 20px;
}
.step-icon {
  margin-bottom: 20px;
}
.step h3 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--fg);
  margin-bottom: 12px;
}
.step p {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--fg2);
}

/* LOOP */
.loop {
  padding: 100px 40px;
  background: var(--bg2);
  border-top: 1px solid var(--border);
}
.loop-header { margin-bottom: 64px; }
.cycle-ring {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0;
  margin-bottom: 40px;
}
.ring-node {
  background: var(--bg3);
  border: 1px solid var(--border);
  padding: 24px 32px;
  min-width: 180px;
  text-align: center;
}
.node-label {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 6px;
}
.node-sub {
  font-size: 0.72rem;
  color: var(--fg2);
  line-height: 1.4;
}
.ring-arrow {
  display: flex;
  align-items: center;
  padding: 0 8px;
  background: var(--bg2);
}
.loop-note {
  text-align: center;
  font-size: 0.85rem;
  color: var(--fg2);
  font-style: italic;
}

/* MARGIN */
.margin {
  padding: 100px 40px;
  border-top: 1px solid var(--border);
}
.margin-grid {
  display: flex;
  align-items: center;
  gap: 0;
  flex-wrap: wrap;
  margin-top: 56px;
  background: var(--bg2);
  border: 1px solid var(--border);
}
.margin-card {
  flex: 1;
  min-width: 160px;
  padding: 40px 32px;
}
.card-arrow {
  padding: 0 8px;
  display: flex;
  align-items: center;
}
.equals {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--fg2);
}
.card-label {
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--fg2);
  margin-bottom: 12px;
}
.card-value {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--fg);
  margin-bottom: 10px;
}
.card-context {
  font-size: 0.78rem;
  color: var(--fg2);
  line-height: 1.5;
}
.profit-card {
  background: var(--accent-dim);
  border-left: 1px solid var(--border);
}
.profit-card .card-value.profit {
  color: var(--accent);
}
.margin-note {
  margin-top: 24px;
  font-size: 0.85rem;
  color: var(--fg2);
  font-style: italic;
  text-align: center;
}

/* FEATURED */
.featured {
  padding: 100px 40px;
  border-top: 1px solid var(--border);
  background: var(--bg2);
}
.featured-inner { max-width: 1200px; margin: 0 auto; }
.featured-label {
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 40px;
}
.featured-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--border);
  background: var(--bg);
  border-radius: 8px;
  overflow: hidden;
}
.featured-info {
  padding: 56px 48px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 20px;
}
.featured-title {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 800;
  color: var(--fg);
  letter-spacing: -0.01em;
  line-height: 1.1;
}
.featured-desc {
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--fg2);
  max-width: 380px;
}
.featured-cats {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}
.cat-badge {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid rgba(245,166,35,0.2);
  padding: 5px 12px;
  border-radius: 100px;
}
.featured-preview {
  background: var(--bg3);
  border-left: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
}
.preview-mock {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 28px 32px;
  width: 100%;
  max-width: 300px;
}
.mock-header {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: 20px;
  text-transform: uppercase;
}
.mock-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--fg2);
  margin-bottom: 10px;
}
.mock-val { font-weight: 600; color: var(--fg); }
.mock-val.accent { color: var(--accent); }
.mock-val.profit { color: #4ADE80; }
.mock-divider { border-top: 1px solid var(--border); margin: 14px 0; }

/* WHY */
.why {
  padding: 100px 40px;
  border-top: 1px solid var(--border);
}
.why-inner { max-width: 1200px; margin: 0 auto; }
.why-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  margin-top: 56px;
  background: var(--border);
  border: 1px solid var(--border);
}
.why-item {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  background: var(--bg);
  padding: 36px 40px;
}
.why-icon { flex-shrink: 0; margin-top: 2px; }
.why-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  color: var(--fg);
  margin-bottom: 8px;
}
.why-desc {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--fg2);
}

/* CLOSING */
.closing {
  padding: 120px 40px 100px;
  border-top: 1px solid var(--border);
  text-align: center;
}
.closing-inner {
  max-width: 600px;
  margin: 0 auto;
}
.closing-headline {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  color: var(--fg);
  line-height: 1.05;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}
.closing-body {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--fg2);
  margin-bottom: 48px;
}

/* FOOTER */
footer {
  padding: 40px;
  border-top: 1px solid var(--border);
}
.footer-inner {
  display: flex;
  align-items: baseline;
  gap: 16px;
  max-width: 1200px;
  margin: 0 auto;
}
.footer-mark {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1rem;
  letter-spacing: 0.05em;
  color: var(--fg);
}
.footer-tag {
  font-size: 0.75rem;
  color: var(--fg2);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .nav { padding: 16px 24px; }
  .hero { padding: 100px 24px 60px; }
  .hero-img-wrap { display: none; }
  .steps { grid-template-columns: 1fr; }
  .featured-card { grid-template-columns: 1fr; }
  .featured-preview { border-left: none; border-top: 1px solid var(--border); }
  .why-grid { grid-template-columns: 1fr; }
  .cycle-ring { flex-direction: column; gap: 0; }
  .margin-grid { flex-direction: column; }
  .card-arrow { transform: rotate(90deg); padding: 8px 0; }
  .how, .featured, .why, .closing { padding: 64px 24px; }
  .stack-visual { display: none; }
  .glow-orb { right: -100px; width: 300px; height: 300px; }
}
@media (max-width: 480px) {
  .hero-actions { flex-direction: column; align-items: flex-start; }
  .featured-info { padding: 32px 24px; }
  .why-item { padding: 28px 24px; }
}