:root {
  --bg: #0b0f14;
  --bg-elevated: #121820;
  --ink: #e8eef5;
  --muted: #9bb0c2;
  --quiet: #6f8496;
  --line: #2a3542;
  --line-soft: rgba(232, 238, 245, 0.08);
  --steel: #7c9cb4;
  --accent: #a8c5a2;
  --danger: #c98984;
  --warn: #c9b48a;
  --font-display: "Fraunces", "Iowan Old Style", Georgia, serif;
  --font-body: "Source Sans 3", "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, Consolas, monospace;
  --pad: clamp(1.25rem, 4vw, 3rem);
  --max: 72rem;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 1.05rem;
  line-height: 1.6;
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: var(--steel);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

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

code,
pre {
  font-family: var(--font-mono);
}

code {
  font-size: 0.9em;
  color: var(--ink);
  background: rgba(232, 238, 245, 0.05);
  border: 1px solid var(--line-soft);
  padding: 0.1em 0.35em;
}

/* —— Atmosphere —— */
.site-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(90rem 42rem at 12% -8%, rgba(124, 156, 180, 0.16), transparent 58%),
    radial-gradient(70rem 36rem at 88% 8%, rgba(168, 197, 162, 0.08), transparent 55%),
    radial-gradient(50rem 40rem at 50% 110%, rgba(20, 40, 50, 0.55), transparent 60%),
    linear-gradient(165deg, #0b0f14 0%, #10161d 48%, #0c1218 100%);
}

.site-bg::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 20%, transparent 75%);
  opacity: 0.55;
}

.site-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.55'/%3E%3C/svg%3E");
  opacity: 0.035;
  mix-blend-mode: overlay;
}

/* —— Header —— */
.top {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.95rem var(--pad);
  border-bottom: 1px solid var(--line-soft);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(14px) saturate(1.1);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.brand img {
  width: 1.55rem;
  height: 1.55rem;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 0.15rem 1.1rem;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--ink);
}

.nav a.nav-github {
  color: var(--accent);
}

/* —— Hero (landing) —— */
.hero {
  position: relative;
  min-height: min(100vh, 56rem);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 6.5rem var(--pad) 4.5rem;
  overflow: hidden;
}

.hero-plane {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, transparent 0%, rgba(11, 15, 20, 0.35) 42%, rgba(11, 15, 20, 0.92) 78%, var(--bg) 100%),
    url("./assets/banner.svg") center top / cover no-repeat;
  opacity: 0.55;
  transform: scale(1.02);
  animation: hero-drift 18s var(--ease) infinite alternate;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 46rem;
}

.brand-lockup {
  margin: 0 0 1.25rem;
  font-family: var(--font-display);
  font-weight: 650;
  font-size: clamp(3.4rem, 11vw, 7.5rem);
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.hero h1 {
  margin: 0 0 1rem;
  max-width: 18ch;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.55rem, 3.2vw, 2.35rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.lede {
  margin: 0;
  max-width: 34rem;
  color: var(--muted);
  font-size: clamp(1.05rem, 1.7vw, 1.2rem);
  line-height: 1.55;
}

.cta {
  margin-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.7rem 1.2rem;
  border: 1px solid var(--line);
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.03em;
  background: rgba(18, 24, 32, 0.55);
  transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.btn:hover {
  border-color: var(--steel);
  color: var(--ink);
  transform: translateY(-1px);
}

.btn.primary {
  border-color: color-mix(in srgb, var(--accent) 65%, var(--line));
  background: color-mix(in srgb, var(--accent) 16%, transparent);
}

.btn.primary:hover {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 24%, transparent);
}

/* —— Sections —— */
.section {
  padding: 4.5rem var(--pad);
  border-top: 1px solid var(--line-soft);
}

.section-inner {
  max-width: var(--max);
  margin: 0 auto;
}

.section-kicker {
  margin: 0 0 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--steel);
}

.section h2 {
  margin: 0 0 0.85rem;
  max-width: 22ch;
  font-family: var(--font-display);
  font-weight: 550;
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  line-height: 1.15;
  letter-spacing: -0.015em;
}

.section-copy {
  margin: 0;
  max-width: 38rem;
  color: var(--muted);
}

/* Process */
.process {
  margin-top: 2.5rem;
  display: grid;
  gap: 0;
}

.process-step {
  display: grid;
  grid-template-columns: 4.5rem 1fr;
  gap: 1rem;
  padding: 1.35rem 0;
  border-top: 1px solid var(--line-soft);
}

.process-step:last-child {
  border-bottom: 1px solid var(--line-soft);
}

.process-index {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--quiet);
  padding-top: 0.35rem;
}

.process-step strong {
  display: block;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 550;
  margin-bottom: 0.25rem;
}

.process-step p {
  margin: 0;
  color: var(--muted);
  max-width: 36rem;
}

/* Receipt showcase */
.receipt-stage {
  margin-top: 2.25rem;
  position: relative;
  border: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(232, 238, 245, 0.03), transparent 28%),
    var(--bg-elevated);
  overflow: hidden;
}

.receipt-stage::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0.55;
  animation: scan 4.5s ease-in-out infinite;
}

.receipt-meta {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--quiet);
}

.receipt-body {
  margin: 0;
  padding: 1.25rem 1.15rem 1.5rem;
  overflow-x: auto;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.86rem;
  line-height: 1.65;
  white-space: pre;
}

.receipt-body .ok {
  color: var(--accent);
}

.receipt-body .bad {
  color: var(--danger);
}

.receipt-body .warn {
  color: var(--warn);
}

.receipt-body .ink {
  color: var(--ink);
}

/* Closing */
.closing {
  text-align: left;
}

.closing .cta {
  margin-top: 1.75rem;
}

/* —— Inner docs —— */
.page {
  padding: 3.5rem var(--pad) 5rem;
}

.page-inner {
  max-width: 44rem;
  margin: 0 auto;
}

.page-kicker {
  margin: 0 0 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--steel);
}

.page h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.1rem, 4vw, 3rem);
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.page h2 {
  margin: 2.4rem 0 0.75rem;
  font-family: var(--font-display);
  font-weight: 550;
  font-size: 1.35rem;
}

.page p,
.page li {
  color: var(--muted);
}

.page strong {
  color: var(--ink);
  font-weight: 600;
}

.page ol,
.page ul {
  padding-left: 1.2rem;
}

.page li + li {
  margin-top: 0.4rem;
}

.page pre {
  margin: 1rem 0 1.25rem;
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
  background: var(--bg-elevated);
  overflow-x: auto;
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.55;
}

/* —— Footer —— */
.site-footer {
  padding: 2rem var(--pad) 2.75rem;
  border-top: 1px solid var(--line-soft);
}

.site-footer-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem 2rem;
  color: var(--quiet);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
}

.site-footer a {
  color: var(--steel);
  text-decoration: none;
}

.site-footer a:hover {
  color: var(--ink);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1.15rem;
}

/* —— Motion —— */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 700ms var(--ease), transform 700ms var(--ease);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@keyframes hero-drift {
  from {
    transform: scale(1.02) translate3d(0, 0, 0);
  }
  to {
    transform: scale(1.06) translate3d(0, -1.5%, 0);
  }
}

@keyframes scan {
  0%,
  100% {
    transform: translateX(-30%);
    opacity: 0.2;
  }
  50% {
    transform: translateX(30%);
    opacity: 0.7;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .hero-plane,
  .receipt-stage::before {
    animation: none;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .btn:hover {
    transform: none;
  }
}

@media (max-width: 720px) {
  .top {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    justify-content: flex-start;
  }

  .hero {
    min-height: auto;
    padding-top: 5rem;
    padding-bottom: 3.5rem;
  }

  .process-step {
    grid-template-columns: 3rem 1fr;
  }
}