/* Shared dark mode styles across pages */

/* Base dark background + text */
body.dark-mode {
  /* Dark theme tokens */
  --dm-bg: #0b1220;
  --dm-surface-1: #111827;
  --dm-surface-2: #162033;
  --dm-text-1: #e6edf3;
  --dm-text-2: rgba(230, 237, 243, 0.76);
  --dm-text-3: rgba(230, 237, 243, 0.6);
  --dm-border: rgba(230, 236, 241, 0.18);
  --dm-accent: #9ecbff;
  --dm-accent-strong: #cfe5ff;

  background: radial-gradient(circle at 12% -10%, rgba(68, 98, 207, 0.38), transparent 45%),
              radial-gradient(circle at 92% 0%, rgba(86, 147, 212, 0.28), transparent 48%),
              linear-gradient(180deg, #0a0e18 0%, var(--dm-bg) 100%);
  color: var(--dm-text-1);
}

/* Global content defaults */
body.dark-mode p,
body.dark-mode li { color: var(--dm-text-1); }
body.dark-mode a { color: var(--dm-accent); text-decoration: underline; text-underline-offset: 2px; }
body.dark-mode a:hover { color: var(--dm-accent-strong); }
body.dark-mode hr { border-color: var(--dm-border); }

/* Header/Nav */
body.dark-mode header {
  background: rgba(20, 24, 36, 0.92);
  border-bottom: 1px solid var(--dm-border);
  box-shadow: 0 6px 22px rgba(8, 15, 30, 0.5);
  color: var(--dm-text-1);
}

body.dark-mode .nav-menu a {
  color: rgba(243, 246, 249, 0.92);
  background: rgba(255, 255, 255, 0.16);
  border: 1px solid rgba(255, 255, 255, 0.28);
  backdrop-filter: blur(12px);
}

body.dark-mode .nav-menu a:hover,
body.dark-mode .nav-menu a.active {
  background: rgba(255, 255, 255, 0.32);
  color: #0e2d34;
  border-color: rgba(255, 255, 255, 0.5);
  box-shadow: 0 14px 32px rgba(8, 15, 30, 0.45);
}

body.dark-mode .mode-toggle {
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.28), rgba(255, 255, 255, 0.06));
  color: var(--dm-text-1);
  border-color: rgba(255, 255, 255, 0.6);
  box-shadow: 0 16px 28px rgba(8, 15, 30, 0.5);
}

body.dark-mode .mode-toggle:hover {
  background: rgba(255, 255, 255, 0.36);
  color: var(--dm-text-1);
}

body.dark-mode .mode-toggle::after { content: "☀️"; }

/* Footer */
body.dark-mode footer {
  background: rgba(20, 24, 36, 0.92);
  color: var(--dm-text-2);
  border-top: 1px solid var(--dm-border);
}

/* Homepage specific elements (safe if absent) */
body.dark-mode .study-tree .tree-node {
  background: rgba(28, 40, 64, 0.6);
  border-color: rgba(215, 222, 229, 0.18);
  color: #e6ecf1;
}

body.dark-mode .tree-root {
  background: rgba(86, 147, 212, 0.25);
  border-color: rgba(86, 147, 212, 0.4);
}

body.dark-mode .tree-branch::before,
body.dark-mode .tree-branch .tree-node::before {
  border-color: rgba(215, 222, 229, 0.18);
}

body.dark-mode .hero figure {
  background: var(--dm-surface-2);
  box-shadow: 0 0 0 14px rgba(12, 18, 32, 0.85), 0 42px 80px rgba(4, 7, 16, 0.55);
  filter: drop-shadow(0 24px 45px rgba(3, 6, 14, 0.5));
}

body.dark-mode .section-head h2,
body.dark-mode .section-head p {
  color: var(--dm-text-1);
}

body.dark-mode .hero-caption {
  color: var(--dm-text-2);
}

/* Dark mode variant for compact pill link */
body.dark-mode .pill-link {
  background: #DBEEF7;
  color: #0e2d34;
  border: 1px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 14px 32px rgba(8, 15, 30, 0.45);
}

/* Image modal overrides */
body.dark-mode .image-modal {
  background: rgba(3, 6, 14, 0.88);
}

body.dark-mode .image-modal img {
  border: 10px solid rgba(12, 18, 32, 0.9);
}

body.dark-mode .image-modal button {
  background: rgba(243, 246, 249, 0.9);
  color: #0e2d34;
}

/* Article page containers */
body.dark-mode .image-container {
  background: var(--dm-surface-2);
  box-shadow: 0 24px 48px rgba(3, 6, 14, 0.5);
  border: 1px solid var(--dm-border);
}

/* Keep technical diagrams readable on dark bg */
body.dark-mode img.diagram-image {
  background: #ffffff;
  border-radius: 8px;
}

body.dark-mode .caption { color: var(--dm-text-2); }

body.dark-mode .highlight-box {
  background: linear-gradient(135deg, rgba(20, 24, 36, 0.80) 0%, rgba(12, 18, 32, 0.80) 100%);
  border-left-color: #f0c66c;
}

body.dark-mode .references {
  background: var(--dm-surface-1);
  border-color: var(--dm-border);
}

/* Table of Contents (left column) for dark mode */
body.dark-mode #toc {
  background: var(--dm-surface-1);
  border-color: var(--dm-border);
  color: var(--dm-text-1);
  box-shadow: 0 18px 36px rgba(8, 15, 30, 0.5);
}
body.dark-mode #toc h3 {
  color: #f0c66c;
  border-bottom-color: rgba(242, 208, 133, 0.6);
}
body.dark-mode #toc a {
  color: var(--dm-text-2);
}
body.dark-mode #toc a:hover {
  background: rgba(255, 255, 255, 0.06);
  color: var(--dm-text-1);
}
body.dark-mode #toc a.active {
  background: linear-gradient(135deg, #DAA520 0%, #B8860B 100%);
  color: #ffffff;
}
body.dark-mode #toc::-webkit-scrollbar-track { background: rgba(255, 255, 255, 0.06); }
body.dark-mode #toc::-webkit-scrollbar-thumb { background: #f0c66c; }
body.dark-mode #toc::-webkit-scrollbar-thumb:hover { background: #d6a84f; }

/* Article headings for contrast */
body.dark-mode h1,
body.dark-mode h2,
body.dark-mode h3 { color: var(--dm-text-1); }
body.dark-mode h2 { border-bottom-color: rgba(242, 208, 133, 0.6); }
body.dark-mode h3 { color: #f0c66c; }

/* Header brand title contrast */
body.dark-mode .brand-title {
  color: var(--dm-text-1);
  text-shadow: 0 1px 0 rgba(0, 0, 0, 0.35);
}