/* ===== Shared page shell: atmosphere background (Plan A) =====
   Scoped to home / about / archives. Linked after page CSS. */

.page-home,
.page-about,
.page-archives {
  --page-bg-top: #e8eef8;
  --page-bg-mid: #f4f7fb;
  --page-bg-bottom: #ffffff;
  --page-glow-a: rgba(37, 99, 235, 0.15);
  --page-glow-b: rgba(79, 70, 229, 0.11);
  --home-border: 1px solid rgba(148, 163, 184, 0.24);
  --home-shadow-sm: 0 14px 36px rgba(15, 23, 42, 0.07);
  --home-shadow: 0 22px 56px rgba(15, 23, 42, 0.09);
  --home-panel-bg: linear-gradient(180deg, rgba(255, 255, 255, 0.98) 0%, rgba(248, 250, 252, 0.94) 100%);

  background-color: var(--page-bg-mid);
  background-image:
    radial-gradient(ellipse 92% 58% at 6% -12%, var(--page-glow-a), transparent 58%),
    radial-gradient(ellipse 78% 52% at 98% 0%, var(--page-glow-b), transparent 54%),
    linear-gradient(180deg, var(--page-bg-top) 0%, var(--page-bg-mid) 260px, var(--page-bg-bottom) 78%);
  background-repeat: no-repeat;
  background-attachment: scroll;
  min-height: 100vh;
  position: relative;
  isolation: isolate;
}

/* Soft engineering dot grid — fades out down the page */
.page-home::before,
.page-about::before,
.page-archives::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0.32;
  background-image: radial-gradient(rgba(15, 23, 42, 0.05) 1px, transparent 1px);
  background-size: 22px 22px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.55) 0%, rgba(0, 0, 0, 0.22) 42%, transparent 88%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.55) 0%, rgba(0, 0, 0, 0.22) 42%, transparent 88%);
}

/* Panel / card lift against the cooler wash */
.page-home .home-panel,
.page-about .about-panel {
  border: var(--home-border);
  background: var(--home-panel-bg);
  box-shadow: var(--home-shadow-sm);
}

.page-archives .archive-card,
.page-archives .archive-series-label {
  border-color: rgba(148, 163, 184, 0.24);
  box-shadow: var(--home-shadow-sm);
}

.page-home .home-hero,
.page-about .about-hero,
.page-archives .archive-hero {
  box-shadow:
    0 28px 64px rgba(15, 23, 42, 0.22),
    0 0 0 1px rgba(255, 255, 255, 0.04) inset;
}

@media (max-width: 700px) {
  .page-home::before,
  .page-about::before,
  .page-archives::before {
    opacity: 0.2;
    background-size: 20px 20px;
  }

  .page-home,
  .page-about,
  .page-archives {
    background-image:
      radial-gradient(ellipse 100% 40% at 50% -5%, var(--page-glow-a), transparent 55%),
      linear-gradient(180deg, var(--page-bg-top) 0%, var(--page-bg-mid) 200px, var(--page-bg-bottom) 70%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-home::before,
  .page-about::before,
  .page-archives::before {
    opacity: 0.18;
  }
}