:root {
  --bg: #0b0f14;
  --ink: #f7f9fc;
  --muted: #b5bfce;
  --line: rgba(255,255,255,.14);
  --accent: #43e0c4;
  --accent-2: #77a8ff;
  --radius: 20px;
  --shadow: 0 16px 34px rgba(0,0,0,.3);
}

body {
  position: relative;
  isolation: isolate;
  background:
    radial-gradient(900px 400px at 10% -10%, rgba(67,224,196,.16), transparent 65%),
    radial-gradient(900px 400px at 100% 0%, rgba(119,168,255,.12), transparent 65%),
    linear-gradient(180deg, #0b0f14 0%, #0a0e13 100%) !important;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.36;
  background-image:
    linear-gradient(rgba(119,168,255,.11) 1px, transparent 1px),
    linear-gradient(90deg, rgba(67,224,196,.11) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: radial-gradient(circle at 50% 18%, rgba(0,0,0,.9), rgba(0,0,0,.45) 62%, transparent 100%);
  -webkit-mask-image: radial-gradient(circle at 50% 18%, rgba(0,0,0,.9), rgba(0,0,0,.45) 62%, transparent 100%);
}

main, nav, footer { position: relative; z-index: 1; }

.card,
.hero > div:first-child,
.hero > div:last-child,
section.card {
  background: rgba(255,255,255,.03) !important;
  border: 1px solid var(--line) !important;
  border-radius: var(--radius) !important;
  box-shadow: var(--shadow);
}

.hero > div:first-child,
.hero > div:last-child {
  padding: 22px;
}

@media (max-width: 640px) {
  .hero > div:first-child,
  .hero > div:last-child {
    padding: 16px;
  }
}

a { text-underline-offset: 2px; }

.page-back-btn {
  margin: 16px 0 0;
  border: 1px solid rgba(255,255,255,.2);
  background: rgba(255,255,255,.04);
  color: #e8f0ff;
  border-radius: 999px;
  font-weight: 700;
  font-size: .86rem;
  padding: 8px 14px;
  cursor: pointer;
}

.page-back-btn:hover {
  border-color: rgba(67,224,196,.6);
  color: #cffff5;
}

.floating-book-cta {
  display: none;
  position: fixed;
  left: 14px;
  right: 14px;
  bottom: max(14px, env(safe-area-inset-bottom));
  z-index: 60;
  text-align: center;
  text-decoration: none;
  color: #072019;
  background: linear-gradient(90deg, var(--accent), #6af2da);
  border: 1px solid rgba(67,224,196,.7);
  border-radius: 999px;
  font-weight: 800;
  font-size: .94rem;
  padding: 13px 16px;
  box-shadow: 0 16px 32px rgba(0,0,0,.35);
}

@media (max-width: 900px) {
  body { padding-bottom: 78px; }
  .floating-book-cta { display: block; }
}