.site-header {
  position: fixed;
  z-index: 50;
  top: var(--space-s);
  left: 50%;
  display: flex;
  width: min(calc(100% - 2 * var(--space-s)), 56rem);
  min-height: var(--nav-height);
  align-items: center;
  justify-content: space-between;
  gap: var(--space-m);
  padding: var(--space-2xs) var(--space-2xs) var(--space-2xs) var(--space-s);
  transform: translateX(-50%);
  border: var(--line-hairline) solid var(--colour-rule-light);
  border-radius: var(--radius-pill);
  background: var(--colour-light-glass);
  box-shadow: var(--shadow-float);
  color: var(--colour-ink);
  backdrop-filter: blur(1.2rem) saturate(1.2);
}

.site-header > a {
  font-size: var(--step--1);
  font-weight: 800;
  letter-spacing: -0.03em;
  text-decoration: none;
}

.site-header nav {
  display: flex;
  align-items: center;
  gap: var(--space-2xs);
}

.nav-toggle {
  display: none;
  min-height: 2.7rem;
  padding: var(--space-2xs) var(--space-s);
  border: var(--line-hairline) solid var(--colour-rule-light);
  background: transparent;
  color: var(--colour-ink);
}

.nav-toggle:hover {
  background: var(--colour-ink);
  color: var(--colour-chalk);
}

.nav-toggle i,
.nav-toggle i::before {
  display: block;
  width: 0.8rem;
  height: var(--line-hairline);
  background: currentColor;
  content: "";
  transition: transform var(--duration-fast) var(--ease-quiet);
}

.nav-toggle i::before {
  transform: translateY(0.25rem);
}

.site-header nav a {
  padding: var(--space-2xs) var(--space-xs);
  border-radius: var(--radius-pill);
  font-size: var(--step--1);
  font-weight: 540;
  text-decoration: none;
  transition:
    background var(--duration-fast) var(--ease-signal),
    color var(--duration-fast) var(--ease-signal);
}

.site-header nav a:hover,
.site-header nav a[aria-current="true"] {
  background: var(--colour-ink);
  color: var(--colour-chalk);
}

.button,
button {
  display: inline-flex;
  min-height: 3.25rem;
  align-items: center;
  justify-content: center;
  gap: var(--space-2xs);
  padding: var(--space-xs) var(--space-m);
  border: var(--line-hairline) solid transparent;
  border-radius: var(--radius-pill);
  background: var(--colour-signal);
  color: var(--colour-ink);
  font-size: var(--step--1);
  font-weight: 700;
  line-height: 1;
  text-decoration: none;
  transition:
    transform var(--duration-fast) var(--ease-quiet),
    background var(--duration-fast) var(--ease-signal);
}

.button:hover,
button:hover {
  transform: translateY(-0.12rem);
  background: var(--colour-chalk);
}

.button--dark {
  background: var(--colour-ink);
  color: var(--colour-chalk);
}

.button--dark:hover {
  background: var(--colour-signal);
  color: var(--colour-ink);
}

.eyebrow,
.system-label,
.section-number {
  font-family: var(--font-mono);
  font-size: var(--step--1);
  letter-spacing: 0.085em;
  line-height: 1.25;
  text-transform: uppercase;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2xs);
}

.eyebrow::before {
  width: 1.85rem;
  height: var(--line-hairline);
  background: currentColor;
  content: "";
}

.chapter-heading {
  max-width: 12ch;
  margin-bottom: var(--space-m);
  font-size: var(--step-6);
}

.chapter-copy {
  font-size: var(--step-1);
  letter-spacing: -0.018em;
}

.qualifier {
  display: grid;
  max-width: 35rem;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-3xs);
  padding: var(--space-3xs);
  border: var(--line-hairline) solid var(--colour-rule-dark);
  border-radius: var(--radius-pill);
  background: var(--colour-night-glass);
  backdrop-filter: blur(1rem);
}

.qualifier label {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}

.qualifier input {
  min-width: 0;
  border: 0;
  outline: 0;
  padding-inline: var(--space-s);
  background: transparent;
  color: var(--colour-chalk);
}

.qualifier input::placeholder {
  color: var(--colour-steel);
}

.qualifier-note,
.form-message {
  grid-column: 1 / -1;
  margin: var(--space-2xs) var(--space-s) var(--space-xs);
  font-size: var(--step--1);
}

.form-message[data-state="error"] {
  color: var(--colour-danger);
}

.form-message[data-state="success"] {
  color: var(--colour-signal);
}

.media-frame {
  position: relative;
  overflow: hidden;
  border: var(--line-hairline) solid var(--colour-rule-dark);
  border-radius: var(--radius-m);
  background: var(--colour-midnight-soft);
}

.media-frame > img,
.media-frame > video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame > video {
  position: absolute;
  z-index: 0;
  inset: 0;
  opacity: 0;
  transition: opacity 900ms var(--ease-quiet);
}

.media-frame > video[data-ready="true"] {
  opacity: 1;
}

.media-frame > figcaption,
.media-frame__veil {
  z-index: 1;
}

.media-frame__veil {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, var(--colour-night-glass), transparent 58%);
  pointer-events: none;
}

.status-light {
  display: inline-block;
  width: 0.58rem;
  height: 0.58rem;
  border-radius: 50%;
  background: var(--colour-signal);
  box-shadow: 0 0 1.4rem var(--colour-signal);
  animation: signal-pulse 2.6s var(--ease-signal) infinite;
}

@keyframes signal-pulse {
  50% {
    opacity: 0.38;
    transform: scale(0.82);
  }
}

.disclosure {
  padding: var(--space-s);
  border: var(--line-hairline) solid currentColor;
  border-radius: var(--radius-s);
  font-family: var(--font-mono);
  font-size: var(--step--1);
  line-height: 1.45;
}

.app-shell {
  position: relative;
  min-height: 35rem;
  overflow: hidden;
  border: var(--line-hairline) solid var(--colour-rule-light);
  border-radius: var(--radius-l);
  background: var(--colour-paper);
  box-shadow: var(--shadow-float);
  color: var(--colour-ink);
}

.app-shell__topbar,
.app-shell__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-s);
  border-bottom: var(--line-hairline) solid var(--colour-rule-light);
}

.app-shell__footer {
  flex-wrap: wrap;
  gap: var(--space-3xs);
  border-top: var(--line-hairline) solid var(--colour-rule-light);
  border-bottom: 0;
}

.app-shell__body {
  display: grid;
  min-height: 27rem;
  align-content: space-between;
  padding: var(--space-m);
  transition: background-color 520ms var(--ease-quiet), transform 520ms var(--ease-quiet);
}

.app-shell__body > * {
  transition: opacity 320ms var(--ease-quiet), transform 520ms var(--ease-quiet);
}

.app-shell__body[data-app-state="compatible"] {
  transform: translateY(0.6rem);
}

.app-shell__body[data-app-state="scheduled"] {
  transform: translateY(0);
  background: color-mix(in srgb, var(--colour-signal) 8%, transparent);
}

.app-shell__body[data-app-state="ready"] {
  transform: translateY(-0.35rem);
  background: color-mix(in srgb, var(--colour-signal) 15%, transparent);
}

.network-panel {
  position: relative;
  min-height: 36rem;
  overflow: hidden;
  border: var(--line-hairline) solid var(--colour-rule-dark);
  border-radius: var(--radius-m);
  background: var(--colour-midnight-soft);
}

.network-node {
  position: absolute;
  width: 0.7rem;
  height: 0.7rem;
  transform: translate(-50%, -50%);
  border: var(--line-hairline) solid var(--colour-chalk);
  border-radius: 50%;
  background: var(--colour-signal);
  box-shadow: 0 0 1.2rem var(--colour-signal);
}

@media (max-width: 46rem) {
  .site-header {
    top: var(--space-xs);
    width: calc(100% - 2 * var(--space-xs));
    min-height: 3.65rem;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .site-header nav {
    position: absolute;
    top: calc(100% + var(--space-2xs));
    right: 0;
    left: 0;
    display: grid;
    padding: var(--space-2xs);
    transform: translateY(-0.6rem) scale(0.98);
    transform-origin: top;
    border: var(--line-hairline) solid var(--colour-rule-light);
    border-radius: var(--radius-m);
    background: var(--colour-light-glass);
    box-shadow: var(--shadow-float);
    opacity: 0;
    pointer-events: none;
    transition:
      opacity var(--duration-fast) var(--ease-signal),
      transform var(--duration-fast) var(--ease-quiet);
    backdrop-filter: blur(1.2rem);
  }

  .site-header[data-menu-open="true"] nav {
    transform: translateY(0) scale(1);
    opacity: 1;
    pointer-events: auto;
  }

  .site-header[data-menu-open="true"] .nav-toggle i {
    transform: rotate(45deg);
  }

  .site-header[data-menu-open="true"] .nav-toggle i::before {
    transform: rotate(-90deg);
  }

  .site-header nav a {
    padding: var(--space-s);
  }

  .qualifier {
    grid-template-columns: 1fr;
    border-radius: var(--radius-m);
  }

  .qualifier input {
    min-height: 3.3rem;
  }

  .chapter-heading {
    max-width: 10ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .media-frame > video {
    display: none;
  }
  .status-light {
    animation: none;
  }
}