/* ==========================================================================
   Optional visual effects — all toggled from _data/theme.yml, rendered as
   data-fx-* attributes on <body> in _layouts/default.html. Disabling a flag
   fully no-ops the corresponding CSS/JS, no page-specific changes needed.
   ========================================================================== */

/* -- paper grain ---------------------------------------------------------- */

.grain-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 999;
  pointer-events: none;
  opacity: 0.05;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

body[data-fx-grain="true"] .grain-overlay {
  display: block;
}

body[data-bg="midnight"] .grain-overlay {
  opacity: 0.08;
  mix-blend-mode: overlay;
}

/* -- scroll reveal ---------------------------------------------------------- */

body[data-fx-reveal="true"] .reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

body[data-fx-reveal="true"] .reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  body[data-fx-reveal="true"] .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* -- underline draw on hover ------------------------------------------------ */

body[data-fx-underline="true"] .article-body a,
body[data-fx-underline="true"] .index-list__excerpt a {
  text-decoration: none;
  background-image: linear-gradient(var(--accent), var(--accent));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0% 1px;
  transition: background-size 0.25s ease;
}

body[data-fx-underline="true"] .article-body a:hover,
body[data-fx-underline="true"] .index-list__excerpt a:hover {
  background-size: 100% 1px;
}