:root {
  --bg: #0e0e10;
  --mono: 'IBM Plex Mono', ui-monospace, monospace;
  --sans: 'Instrument Sans', system-ui, sans-serif;
  --sticky-top: 3rem;
  --layer-offset: 1.35rem;
  --layer-scroll: 38vh;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: #e8e6e3;
  line-height: 1.5;
  overflow-x: hidden;
}

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.65rem 1.25rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  background: rgba(14, 14, 16, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.nav a {
  color: #6b6966;
  text-decoration: none;
}

.nav a:hover { color: #c4a574; }

.depth {
  color: #c4a574;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.stack-viewport {
  padding: 0.5rem 1.25rem 2rem;
  max-width: 520px;
  margin: 0 auto;
}

.layer {
  position: sticky;
  min-height: auto;
  padding-bottom: var(--layer-scroll);
  margin-bottom: -calc(var(--layer-scroll) - var(--layer-offset) * 2);
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.07);
  box-shadow:
    0 12px 28px rgba(0, 0, 0, 0.35),
    0 2px 6px rgba(0, 0, 0, 0.2);
}

.layer-0 {
  top: var(--sticky-top);
  z-index: 1;
  background: #1a1a1e;
  margin-bottom: -calc(var(--layer-scroll) - var(--layer-offset));
}

.layer-1 {
  top: calc(var(--sticky-top) + var(--layer-offset));
  z-index: 2;
  background: #222228;
}

.layer-2 {
  top: calc(var(--sticky-top) + var(--layer-offset) * 2);
  z-index: 3;
  background: #2a2a32;
}

.layer-3 {
  top: calc(var(--sticky-top) + var(--layer-offset) * 3);
  z-index: 4;
  background: #32323c;
}

.layer-4 {
  top: calc(var(--sticky-top) + var(--layer-offset) * 4);
  z-index: 5;
  background: #3a3a46;
  margin-bottom: 0;
  padding-bottom: 1rem;
}

.layer-inner {
  padding: 1.25rem 1.35rem 1.35rem;
}

.layer-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 0.75rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  font-family: var(--mono);
  font-size: 0.62rem;
}

.layer-id {
  color: #c4a574;
  font-weight: 600;
  letter-spacing: 0.06em;
}

.layer-name {
  color: #6b6966;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.layer-link {
  margin-left: auto;
  color: #8b9cb3;
  text-decoration: none;
  font-size: 0.6rem;
}

.layer-link:hover { color: #c4a574; }

.layer h1 {
  font-size: clamp(2rem, 8vw, 2.65rem);
  font-weight: 600;
  letter-spacing: -0.04em;
  margin-bottom: 0.2rem;
  line-height: 1.1;
}

.layer h2 {
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 0.35rem;
}

.tagline {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: #6b6966;
  margin-bottom: 0.5rem;
}

.body {
  color: #a8a6a1;
  font-size: 0.9rem;
  margin-bottom: 0.65rem;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 0.5rem;
}

.chips span {
  font-family: var(--mono);
  font-size: 0.58rem;
  padding: 0.2rem 0.45rem;
  background: rgba(196, 165, 116, 0.1);
  color: #c4a574;
  border: 1px solid rgba(196, 165, 116, 0.2);
  border-radius: 3px;
}

.avail {
  font-family: var(--mono);
  font-size: 0.65rem;
  color: #7eb87a;
}

.stack-list {
  list-style: none;
  font-family: var(--mono);
  font-size: 0.68rem;
  color: #6b6966;
}

.sat-links {
  font-family: var(--mono);
  font-size: 0.68rem;
  margin-bottom: 0.85rem;
}

.sat-links a {
  color: #8b9cb3;
  text-decoration: none;
}

.sat-links a:hover { color: #c4a574; }

.sat-links .sep {
  color: #3a3a40;
  margin: 0 0.25rem;
}

.contact-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.65rem;
}

.btn {
  font-family: var(--mono);
  font-size: 0.72rem;
  padding: 0.5rem 0.85rem;
  background: #c4a574;
  color: #0e0e10;
  text-decoration: none;
  font-weight: 600;
  border-radius: 4px;
}

.btn:hover { background: #e8d4b0; }

.btn-ghost {
  background: transparent;
  color: #c4a574;
  border: 1px solid rgba(196, 165, 116, 0.35);
}

.btn-ghost:hover {
  background: rgba(196, 165, 116, 0.08);
}

.guarantees {
  font-family: var(--mono);
  font-size: 0.6rem;
  color: #5a5854;
}

.site-foot {
  display: flex;
  justify-content: space-between;
  max-width: 520px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
  font-family: var(--mono);
  font-size: 0.62rem;
  color: #4a4844;
}

.site-foot a {
  color: #4a4844;
  text-decoration: none;
}

.site-foot a:hover { color: #c4a574; }

.stack-ruler {
  position: fixed;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 50;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  font-family: var(--mono);
  font-size: 0.5rem;
  color: #2e2e34;
  pointer-events: none;
}

.stack-ruler span {
  transition: color 0.15s;
}

.stack-ruler span.active {
  color: #c4a574;
}

.layer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 8px 8px 0 0;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.08), transparent);
  pointer-events: none;
}

@media (max-width: 700px) {
  .stack-ruler { display: none; }
  :root {
    --layer-offset: 1rem;
    --layer-scroll: 32vh;
  }
}