/* Shared chrome for technique demos + site pages */
:root {
  --bg: #0b0d12;
  --panel: rgba(18, 22, 31, 0.82);
  --panel-2: rgba(26, 32, 48, 0.88);
  --border: #2a3348;
  --text: #e8edf7;
  --muted: #8b97b0;
  --accent: #6ec8ff;
  --accent-2: #ffb86b;
  --good: #7ddea2;
  --warn: #f0c674;
  --mono: "SF Mono", "JetBrains Mono", ui-monospace, Menlo, monospace;
  --sans: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  min-height: 100%;
  /* Do not paint an opaque full-page bg — site-bg.js owns the backdrop.
     has-site-bg / site-bg-static override as needed. */
  background: transparent;
  color: var(--text);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.5;
}

/*
 * WebGL background (site-bg.js) lives on <html> with z-index: -1.
 * html/body MUST be transparent or they paint over the canvas.
 */
#site-bg {
  position: fixed !important;
  inset: 0 !important;
  width: 100vw !important;
  height: 100vh !important;
  z-index: -1 !important;
  pointer-events: none !important;
  display: block !important;
}

html.has-site-bg,
html.has-site-bg body {
  background: transparent !important;
  background-color: transparent !important;
}

/* Quiet fallback if WebGL fails or reduced-motion */
html.site-bg-static,
html.site-bg-static body {
  background:
    radial-gradient(ellipse 70% 50% at 15% 10%, rgba(40, 90, 160, 0.22), transparent 55%),
    radial-gradient(ellipse 60% 45% at 90% 80%, rgba(80, 40, 120, 0.16), transparent 50%),
    #0a0c12 !important;
  background-attachment: fixed !important;
}

/* Base page color only when bg script hasn't run yet */
html:not(.has-site-bg) {
  background: #0b0d12;
}

.site-content,
.wrap,
.page,
.shell {
  position: relative;
  z-index: 1;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Demo split view */
.layout {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(280px, 380px) 1fr;
  height: 100vh;
}

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
    grid-template-rows: 42vh 1fr;
  }
}

.layout .panel {
  background: linear-gradient(
    180deg,
    rgba(18, 22, 31, 0.92) 0%,
    rgba(14, 18, 25, 0.94) 100%
  );
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}
.layout .stage {
  background: #05070c;
  z-index: 1;
}

.panel {
  overflow: auto;
  background: linear-gradient(180deg, var(--panel) 0%, rgba(14, 18, 25, 0.94) 100%);
  border-right: 1px solid var(--border);
  padding: 1.1rem 1.2rem 2rem;
}

.panel header {
  margin-bottom: 1rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border);
}

.crumb {
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 0.35rem;
}

.panel h1 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 0.35rem;
  letter-spacing: -0.02em;
}

.panel .lede {
  color: var(--muted);
  margin: 0;
  font-size: 13px;
}

.panel h2 {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin: 1.25rem 0 0.45rem;
}

.panel p, .panel li {
  color: #c5cddd;
  font-size: 13px;
}

.panel ul {
  margin: 0.3rem 0 0.5rem;
  padding-left: 1.15rem;
}

.panel code, .code {
  font-family: var(--mono);
  font-size: 11.5px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.1em 0.35em;
}

pre.codeblock {
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1.45;
  background: #0a0e16;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.75rem 0.85rem;
  overflow-x: auto;
  color: #b8c7e0;
  margin: 0.4rem 0 0.7rem;
}

.tagrow {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin: 0.65rem 0 0.25rem;
}

.tag {
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.2rem 0.45rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--muted);
  background: var(--panel-2);
}

.tag.ref { border-color: #3a5068; color: var(--accent); }
.tag.stack { border-color: #4a3f28; color: var(--accent-2); }

.controls {
  display: grid;
  gap: 0.55rem;
  margin-top: 0.35rem;
}

.control {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.2rem 0.6rem;
  align-items: center;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.55rem 0.7rem;
}

.control label {
  font-size: 12px;
  color: var(--text);
}

.control .val {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent);
}

.control input[type="range"] {
  grid-column: 1 / -1;
  width: 100%;
  accent-color: var(--accent);
}

.control.checkbox {
  grid-template-columns: auto 1fr;
}

.control.checkbox input { accent-color: var(--accent); }

.note {
  margin-top: 0.8rem;
  padding: 0.65rem 0.75rem;
  border-left: 3px solid var(--accent-2);
  background: rgba(255, 184, 107, 0.06);
  border-radius: 0 8px 8px 0;
  color: #d8c9a8;
  font-size: 12.5px;
}

.note strong { color: var(--accent-2); }

.stage {
  position: relative;
  min-height: 0;
  background: #05070c;
}

.stage canvas {
  display: block;
  width: 100% !important;
  height: 100% !important;
}

.hud {
  position: absolute;
  left: 12px;
  bottom: 12px;
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  pointer-events: none;
}

.hud span {
  font-family: var(--mono);
  font-size: 11px;
  padding: 0.3rem 0.5rem;
  background: rgba(8, 12, 20, 0.75);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--muted);
  backdrop-filter: blur(6px);
}

.nav-next {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
  margin-top: 1.4rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border);
  font-size: 12px;
}

.eq {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--good);
  background: rgba(125, 222, 162, 0.06);
  border: 1px solid rgba(125, 222, 162, 0.25);
  border-radius: 6px;
  padding: 0.45rem 0.6rem;
  margin: 0.4rem 0;
}