/*
 * Heliopause field-note treatment.
 * A warm plasma palette and dense particle field distinguish this pressure
 * boundary from the cooler Kuiper Belt, Oort Cloud and icy-world diagrams.
 */
.heliopause-page-visual {
  border-color: rgba(246, 232, 155, 0.18);
  background:
    radial-gradient(circle at 12% 50%, rgba(255, 238, 137, 0.12), transparent 19%),
    radial-gradient(ellipse at 76% 48%, rgba(232, 153, 88, 0.09), transparent 43%),
    linear-gradient(145deg, rgba(41, 24, 20, 0.2), rgba(8, 13, 22, 0.5));
}

.helio-crossing-line {
  fill: rgba(255, 247, 183, 0.5);
  stroke: none;
}

.helio-plasma-particle {
  transition: opacity 0.3s ease, filter 0.3s ease;
}

.heliopause-page-visual:hover .helio-plasma-particle {
  filter: drop-shadow(0 0 2px rgba(255, 242, 154, 0.68));
}

.heliopause-page-visual:hover .helio-crossing-line {
  fill: rgba(255, 250, 205, 0.78);
}

[data-theme="light"] .heliopause-page-visual {
  border-color: rgba(172, 139, 58, 0.2);
  background:
    radial-gradient(circle at 12% 50%, rgba(232, 199, 74, 0.17), transparent 19%),
    radial-gradient(ellipse at 76% 48%, rgba(194, 143, 65, 0.1), transparent 43%),
    linear-gradient(145deg, rgba(255, 246, 235, 0.84), rgba(240, 244, 248, 0.76));
}

@media (prefers-reduced-motion: reduce) {
  .helio-plasma-particle {
    filter: none;
  }
}