:root {
  --ink: #0f172a;
  --ink-soft: #334155;
  --paper: #f8fafc;
  --line: #e2e8f0;
  --night: #0b1220;
  --night-2: #1e293b;
  --on-night: #f8fafc;
  --on-night-soft: #cbd5e1;
  --volt: #facc15;
  --accent: #92400e; /* amber for use on light backgrounds (AA contrast) */
  --focus: #2563eb;
  --radius: 14px;
  --max: 1120px;
  --header-h: 64px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 8px); }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

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

a { color: inherit; }

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
  border-radius: 4px;
}

.container {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: clamp(16px, 4vw, 32px);
}

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -100px;
  z-index: 100;
  padding: 10px 16px;
  background: var(--volt);
  color: var(--ink);
  font-weight: 700;
  border-radius: 8px;
  text-decoration: none;
}
.skip-link:focus { top: 12px; }

/* Placeholders: obvious so nothing unconfirmed ships by accident */
.placeholder {
  background: rgba(250, 204, 21, 0.18);
  outline: 1px dashed currentColor;
  outline-offset: 1px;
  border-radius: 3px;
  padding: 0 4px;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 18, 32, 0.9);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
}

.brand {
  color: var(--on-night);
  font-weight: 800;
  letter-spacing: -0.01em;
  text-decoration: none;
  font-size: 1.1rem;
}

.nav-menu {
  display: flex;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-menu a {
  display: block;
  padding: 8px 12px;
  color: var(--on-night-soft);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: 8px;
  transition: color .15s, background-color .15s;
}
.nav-menu a:hover,
.nav-menu a[aria-current="true"] {
  color: var(--on-night);
  background: rgba(255, 255, 255, 0.08);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  cursor: pointer;
  position: relative;
}
.nav-toggle-bar,
.nav-toggle-bar::before,
.nav-toggle-bar::after {
  position: absolute;
  left: 11px;
  width: 22px;
  height: 2px;
  background: var(--on-night);
  border-radius: 2px;
  transition: transform .2s, opacity .2s;
}
.nav-toggle-bar { top: 21px; }
.nav-toggle-bar::before,
.nav-toggle-bar::after { content: ""; left: 0; }
.nav-toggle-bar::before { top: -7px; }
.nav-toggle-bar::after { top: 7px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar::before { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar::after { transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 760px) {
  .nav-toggle { display: block; }
  .js .nav-menu {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    padding: 8px clamp(16px, 4vw, 32px) 16px;
    background: var(--night);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    display: none;
  }
  .js .nav-menu.is-open { display: flex; }
  .nav-menu a { padding: 12px; font-size: 1rem; }
  /* Without JS, show the links inline and let them wrap */
  html:not(.js) .nav-toggle { display: none; }
  html:not(.js) .nav { height: auto; flex-wrap: wrap; padding-block: 8px; }
  html:not(.js) .nav-menu { flex-wrap: wrap; }
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  min-height: calc(100svh - var(--header-h));
  display: grid;
  align-items: center;
  color: var(--on-night);
  background:
    radial-gradient(1200px 600px at 50% -10%, #334155 0%, transparent 60%),
    linear-gradient(180deg, var(--night-2) 0%, var(--night) 100%);
}

.sky { position: absolute; inset: 0; pointer-events: none; }

.cloud {
  position: absolute;
  border-radius: 50%;
  background: radial-gradient(closest-side, rgba(148, 163, 184, 0.28), transparent);
  filter: blur(8px);
  animation: drift 40s linear infinite alternate;
}
.cloud-1 { width: 60vw; height: 22vw; top: 4%; left: -12%; }
.cloud-2 { width: 50vw; height: 18vw; top: 18%; right: -14%; animation-duration: 55s; }
.cloud-3 { width: 70vw; height: 24vw; bottom: -6%; left: 14%; animation-duration: 70s; }

.flash {
  position: absolute;
  inset: 0;
  background: radial-gradient(800px 400px at 60% 10%, rgba(254, 240, 138, 0.35), transparent 70%);
  opacity: 0;
  animation: flash 9s infinite;
}

@keyframes drift { to { transform: translateX(6vw); } }
@keyframes flash {
  0%, 88%, 100% { opacity: 0; }
  89% { opacity: 1; }
  90% { opacity: 0.2; }
  91.5% { opacity: 0.8; }
  93% { opacity: 0; }
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1fr minmax(0, 2.2fr) 1fr;
  grid-template-areas:
    "a copy b"
    "c copy d";
  gap: clamp(16px, 3vw, 40px);
  align-items: center;
  padding-block: clamp(40px, 8vh, 96px);
}

.critter { margin: 0; width: clamp(96px, 14vw, 180px); justify-self: center; }
.critter svg { width: 100%; height: auto; filter: drop-shadow(0 10px 18px rgba(0, 0, 0, 0.45)); }
.critter-a { grid-area: a; animation: bob 5s ease-in-out infinite; }
.critter-b { grid-area: b; animation: bob 6s ease-in-out -1.5s infinite; }
.critter-c { grid-area: c; animation: bob 5.5s ease-in-out -3s infinite; }
.critter-d { grid-area: d; animation: bob 6.5s ease-in-out -2s infinite; }

@keyframes bob {
  0%, 100% { transform: translateY(0) rotate(-2deg); }
  50% { transform: translateY(-12px) rotate(2deg); }
}

.hero-copy { grid-area: copy; text-align: center; }

.hero h1 {
  margin: 0 0 0.35em;
  font-size: clamp(2.4rem, 6.4vw, 5.4rem);
  line-height: 1.02;
  font-weight: 850;
  letter-spacing: -0.03em;
  text-wrap: balance;
}

.hero-sub {
  margin: 0 auto 1.75rem;
  max-width: 36ch;
  color: var(--on-night-soft);
  font-size: clamp(1rem, 1.6vw, 1.2rem);
}

.btn {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 999px;
  background: var(--volt);
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
  transition: transform .15s, box-shadow .15s;
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 8px 24px rgba(250, 204, 21, 0.3); }
.btn:focus-visible { outline-color: #fff; }

@media (max-width: 760px) {
  .hero { min-height: auto; }
  .hero-grid {
    grid-template-columns: 1fr 1fr;
    grid-template-areas:
      "a b"
      "copy copy"
      "c d";
    row-gap: 24px;
  }
  .critter { width: clamp(84px, 28vw, 130px); }
}

/* ---------- Chapters ---------- */
.chapters { padding-block: clamp(56px, 10vw, 112px); }

.chapter {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 24px;
  padding-block: clamp(32px, 5vw, 56px);
  border-top: 1px solid var(--line);
}
.chapter:first-child { border-top: 0; padding-top: 0; }

.eyebrow {
  margin: 0.35rem 0 0;
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.chapter-body { max-width: 68ch; }

.chapter h2 {
  margin: 0;
  font-size: clamp(1.75rem, 3.6vw, 2.5rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.meta {
  margin: 0.35rem 0 1rem;
  color: var(--ink-soft);
  font-weight: 500;
}

.chapter p { color: var(--ink-soft); }

.highlights { margin: 1rem 0 0; padding-left: 1.2rem; color: var(--ink-soft); }
.highlights li + li { margin-top: 0.4rem; }
.highlights li::marker { color: var(--accent); }

@media (max-width: 560px) {
  .chapter { grid-template-columns: 1fr; gap: 4px; }
}

/* ---------- Contact / footer ---------- */
.contact {
  background: var(--night);
  color: var(--on-night);
  padding-block: clamp(56px, 9vw, 96px);
}
.contact h2 {
  margin: 0 0 1.25rem;
  font-size: clamp(1.75rem, 3.6vw, 2.5rem);
  letter-spacing: -0.02em;
}
.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.contact-links a {
  display: inline-block;
  padding: 10px 18px;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 999px;
  text-decoration: none;
  color: var(--on-night);
  transition: border-color .15s, background-color .15s;
}
.contact-links a:hover { border-color: var(--volt); background: rgba(250, 204, 21, 0.08); }
.contact-links a:focus-visible { outline-color: var(--volt); }

.site-footer {
  background: var(--night);
  color: var(--on-night-soft);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 0.9rem;
}
.site-footer p { margin: 0; padding-block: 20px; }

.site-header :focus-visible,
.hero :focus-visible { outline-color: var(--volt); }

/* ---------- 404 ---------- */
.notfound {
  min-height: 100svh;
  display: grid;
  place-items: center;
  text-align: center;
  color: var(--on-night);
  background: linear-gradient(180deg, var(--night-2), var(--night));
}
.notfound h1 { font-size: clamp(2rem, 6vw, 3.5rem); margin: 0 0 0.5rem; letter-spacing: -0.02em; }
.notfound p { color: var(--on-night-soft); margin: 0 0 1.5rem; }
.notfound :focus-visible { outline-color: var(--volt); }

/* ---------- Motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}