/* =========================================================
   Tokens — dark-only (no light/dark toggle). Validated categorical
   palette kept for data encoding (category dots/badges); everything
   else (buttons, glows, headings) uses a vibrant playful accent set.
   ========================================================= */
:root {
  color-scheme: dark;
  --page: #100e17;
  --surface: #1b1826;
  --surface-2: #251f34;
  --text-primary: #ffffff;
  --text-secondary: #cbc4de;
  --text-muted: #948cae;
  --border: rgba(255,255,255,0.12);
  --gridline: #362e4a;

  /* Categorical (data encoding — keep validated CVD-safe hues) */
  --cat-caffeine: #3987e5;
  --cat-illicit: #d95926;
  --cat-peptide: #199e70;
  --cat-pharmaceutical: #c98500;
  --cat-supplement: #d55181;
  --cat-vitamin: #3fbf3f;
  --cat-other: #9085e9;

  --ev-rct: #184f95;
  --ev-observational: #256abf;
  --ev-mixed: #3987e5;
  --ev-animal: #6da7ec;
  --ev-anecdotal: #9ec5f4;

  /* Playful accent set */
  --accent-pink: #ff5fa2;
  --accent-purple: #9b5cf6;
  --accent-orange: #ffab2e;
  --accent-teal: #2fd8c4;
  --accent-gradient: linear-gradient(135deg, var(--accent-purple), var(--accent-pink) 60%, var(--accent-orange));
  --focus-ring: var(--accent-pink);
  --radius: 22px;
  --radius-lg: 30px;
  --bounce: cubic-bezier(0.34, 1.56, 0.64, 1);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background:
    radial-gradient(1200px 600px at 15% -10%, rgba(155,92,246,0.20), transparent 60%),
    radial-gradient(900px 500px at 100% 0%, rgba(255,95,162,0.14), transparent 55%),
    var(--page);
  color: var(--text-primary);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  line-height: 1.5;
}

.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--surface); color: var(--text-primary);
  padding: 8px 14px; border-radius: 0 0 8px 0; z-index: 100;
}
.skip-link:focus { left: 0; }

:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}

/* =========================================================
   Layout
   ========================================================= */
.site-header {
  display: flex; flex-wrap: wrap; gap: 16px;
  align-items: center; justify-content: space-between;
  padding: 20px 24px; border-bottom: 1px solid var(--border);
  background: rgba(27,24,38,0.7);
  backdrop-filter: blur(10px);
  position: sticky; top: 0; z-index: 10;
}
.brand { display: flex; align-items: center; gap: 14px; }
.logo { width: 44px; height: 44px; border-radius: 14px; box-shadow: 0 4px 16px rgba(155,92,246,0.35); }
.site-title {
  margin: 0; font-weight: 800; font-size: 1.25rem; letter-spacing: -0.01em;
  background: var(--accent-gradient);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.site-tagline { margin: 0; color: var(--text-secondary); font-size: 0.92rem; }

main { max-width: 1080px; margin: 0 auto; padding: 28px 24px; }
section { margin-bottom: 52px; }
h1, h2 { letter-spacing: -0.02em; }
h2 { font-size: 1.7rem; font-weight: 800; }
.section-sub { color: var(--text-secondary); margin-top: -6px; }
.muted { color: var(--text-muted); }

.disclaimer {
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 22px; margin-bottom: 40px;
}
.disclaimer p { margin: 0; color: var(--text-secondary); }

/* Brain explorer */
.brain-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; margin-top: 16px; }
@media (max-width: 760px) { .brain-layout { grid-template-columns: 1fr; } }

.brain-diagram-wrap {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 16px;
  box-shadow: 0 20px 50px -20px rgba(155,92,246,0.35);
}
#brain-svg { width: 100%; height: auto; }

.cerebrum-shape { fill: #efe0fb; stroke: #2a1a3a; stroke-width: 4; stroke-linejoin: round; }
.cerebellum-shape { fill: #d7bdf3; stroke: #2a1a3a; stroke-width: 4; stroke-linejoin: round; }
.brainstem-shape { fill: #d7bdf3; stroke: #2a1a3a; stroke-width: 4; stroke-linejoin: round; }

.region {
  opacity: 0.55; stroke: rgba(0,0,0,0.55); stroke-width: 2;
  cursor: pointer; transition: opacity 0.2s var(--bounce), transform 0.2s var(--bounce), filter 0.2s var(--bounce);
  transform-box: fill-box; transform-origin: center;
}
#region-pfc { fill: var(--accent-pink); }
#region-acc { fill: var(--accent-purple); }
#region-striatum { fill: var(--accent-teal); }
#region-accumbens { fill: var(--accent-orange); }
#region-amygdala { fill: #ff8a5c; }
#region-locus-coeruleus { fill: #5cc8ff; }

.region:hover { opacity: 0.8; transform: scale(1.06); }
.region.active { opacity: 0.95; transform: scale(1.1); stroke-width: 3; filter: drop-shadow(0 0 10px rgba(255,255,255,0.35)); }
.region:focus-visible { outline: 3px solid var(--focus-ring); outline-offset: 2px; }

.region-list {
  list-style: none; margin: 0 0 16px; padding: 0;
  display: flex; flex-wrap: wrap; gap: 8px;
}
.region-list button {
  font: inherit; font-size: 0.9rem; font-weight: 600;
  background: var(--surface-2); color: var(--text-primary);
  border: 1px solid var(--border); border-radius: 999px;
  padding: 8px 16px; cursor: pointer;
  transition: transform 0.15s var(--bounce), background 0.15s ease;
}
.region-list button:hover { transform: translateY(-2px) scale(1.03); }
.region-list button[aria-pressed="true"] {
  background: var(--accent-gradient); color: #fff; border-color: transparent;
}

.region-detail {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 22px; min-height: 120px;
}
.region-detail h3 { margin-top: 0; }
.region-detail .effect-list { list-style: none; margin: 12px 0 0; padding: 0; }
.region-detail .effect-list li {
  padding: 10px 0; border-top: 1px solid var(--gridline);
  display: flex; flex-direction: column; gap: 2px;
}

/* Filters */
.filters {
  display: flex; flex-wrap: wrap; gap: 20px; align-items: end;
  margin: 16px 0;
}
.filter-group { display: flex; flex-direction: column; gap: 6px; }
.filter-group label { font-size: 0.85rem; color: var(--text-secondary); }
#category-filters { flex-direction: row; flex-wrap: wrap; align-self: end; }
.cat-chip {
  font: inherit; font-size: 0.85rem; font-weight: 600;
  border-radius: 999px; padding: 8px 16px; cursor: pointer;
  border: 2px solid transparent; background: var(--surface-2); color: var(--text-primary);
  transition: transform 0.15s var(--bounce), border-color 0.15s ease;
}
.cat-chip:hover { transform: translateY(-2px) scale(1.04); }
.cat-chip[aria-pressed="true"] { border-color: var(--accent-pink); }
.cat-chip .dot { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 6px; }

select, input[type="search"] {
  font: inherit; padding: 10px 12px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text-primary);
}
select:focus, input[type="search"]:focus { border-color: var(--accent-pink); }

.legend { font-size: 0.85rem; color: var(--text-secondary); }
.ev-badge {
  display: inline-block; font-size: 0.75rem; font-weight: 700;
  color: #fff; border-radius: 8px; padding: 3px 9px; margin-right: 4px;
}
.ev-rct { background: var(--ev-rct); }
.ev-observational { background: var(--ev-observational); }
.ev-mixed { background: var(--ev-mixed); }
.ev-animal { background: var(--ev-animal); color: #0b0b0b; }
.ev-anecdotal { background: var(--ev-anecdotal); color: #0b0b0b; }

/* Substance grid */
.substance-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 18px; margin-top: 8px;
}
.substance-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; display: flex; flex-direction: column; gap: 10px;
  transition: transform 0.2s var(--bounce), box-shadow 0.2s var(--bounce), border-color 0.2s ease;
}
.substance-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 18px 40px -18px rgba(155,92,246,0.5);
  border-color: rgba(255,95,162,0.4);
}
.substance-card h3 { margin: 0; font-size: 1.08rem; }
.cat-badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 0.75rem; font-weight: 700; color: var(--text-primary);
  border: 1px solid var(--border); border-radius: 999px; padding: 3px 11px;
  width: fit-content;
}
.cat-badge .dot { width: 10px; height: 10px; border-radius: 50%; }
.mech-tags { display: flex; flex-wrap: wrap; gap: 6px; font-size: 0.78rem; color: var(--text-secondary); }
.mech-tags span { background: var(--surface-2); border-radius: 8px; padding: 3px 9px; }

.card-detail { display: none; border-top: 1px solid var(--gridline); padding-top: 10px; margin-top: 4px; }
.substance-card.expanded .card-detail { display: block; }
.expand-btn {
  align-self: flex-start; background: none; border: none; color: var(--accent-pink);
  cursor: pointer; font: inherit; font-weight: 700; padding: 4px 0;
  transition: transform 0.15s var(--bounce);
}
.expand-btn:hover { transform: translateX(3px); }

.site-footer {
  border-top: 1px solid var(--border); padding: 24px; margin-top: 20px;
  color: var(--text-muted); font-size: 0.85rem; text-align: center;
}
.footer-ref { margin-top: 6px; }
.footer-ref a { color: var(--accent-pink); }