/* Quantum instrument panel — dark carbon, bright(amber)/dark(cyan) duotone */
:root {
  --bg: #0a0c10;
  --bg-2: #10141b;
  --panel: #0e1219;
  --ink: #e8ecf2;
  --ink-dim: #8b95a6;
  --line: #1e2530;
  --line-2: #2b3442;
  --bright: #ff9e3d;      /* superradiant / bright modes */
  --bright-glow: #ff6b1a;
  --dark: #35d0e6;        /* subradiant / dark modes */
  --dark-glow: #00a3c4;
  --accent: #f2c14e;
  --danger: #ff5d5d;
  --grid: rgba(120, 140, 170, 0.09);
  --mono: "Space Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
  --display: "Syne", "Space Mono", system-ui, sans-serif;
}

* { box-sizing: border-box; }
html, body { margin: 0; background: var(--bg); color: var(--ink); }
body {
  font-family: var(--mono);
  font-size: 14px;
  line-height: 1.5;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(255, 110, 26, 0.06), transparent 60%),
    radial-gradient(1000px 700px at -10% 110%, rgba(0, 163, 196, 0.07), transparent 55%),
    var(--bg);
  min-height: 100vh;
}

/* atmospheric overlays */
.scanline { position: fixed; inset: 0; pointer-events: none; z-index: 999;
  background: repeating-linear-gradient(to bottom, transparent 0 3px, rgba(0,0,0,0.14) 3px 4px);
  mix-blend-mode: overlay; opacity: 0.5; }
.grain { position: fixed; inset: 0; pointer-events: none; z-index: 998; opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E"); }

/* masthead */
.masthead { display: flex; justify-content: space-between; align-items: center;
  padding: 22px 34px; border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(255,158,61,0.04), transparent); }
.mast-left { display: flex; gap: 18px; align-items: center; }
.sigil { font-family: var(--display); font-size: 44px; font-weight: 800;
  color: var(--bright); text-shadow: 0 0 22px var(--bright-glow);
  line-height: 1; transform: translateY(-2px); }
.mast-title h1 { font-family: var(--display); font-weight: 800; letter-spacing: 0.02em;
  font-size: 25px; margin: 0; }
.mast-title p { margin: 3px 0 0; color: var(--ink-dim); font-size: 12.5px; }
.mono { font-family: var(--mono); }
.mast-readout { display: flex; gap: 20px; }
.mast-readout span { display: flex; flex-direction: column; font-size: 15px; color: var(--dark); }
.mast-readout span::before { content: attr(data-k); font-size: 10px; color: var(--ink-dim);
  letter-spacing: 0.08em; text-transform: uppercase; }

/* stepbar */
.stepbar { display: flex; gap: 2px; padding: 0 34px; border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 50; background: rgba(10,12,16,0.92);
  backdrop-filter: blur(8px); overflow-x: auto; }
.step-btn { appearance: none; background: none; border: none; color: var(--ink-dim);
  font-family: var(--mono); font-size: 12px; padding: 14px 16px; cursor: pointer;
  border-bottom: 2px solid transparent; white-space: nowrap; transition: color .18s, border-color .18s; }
.step-btn:hover { color: var(--ink); }
.step-btn .n { color: var(--line-2); margin-right: 8px; }
.step-btn.is-active { color: var(--bright); border-bottom-color: var(--bright); }
.step-btn.is-active .n { color: var(--bright); }

/* stage & panels */
.stage { max-width: 1240px; margin: 0 auto; padding: 20px 34px 80px; }
.panel { display: none; animation: rise .45s cubic-bezier(.2,.8,.2,1); }
.panel.is-active { display: block; }
@keyframes rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
.panel-head { margin: 22px 0 18px; max-width: 780px; }
.panel-head h2 { font-family: var(--display); font-weight: 700; font-size: 24px; margin: 0 0 6px; }
.panel-head .idx { color: var(--bright); font-size: 15px; margin-right: 12px;
  font-family: var(--mono); vertical-align: 2px; }
.panel-head p { color: var(--ink-dim); font-size: 13px; margin: 0; }

.panel-body { border: 1px solid var(--line); border-radius: 4px; background:
  linear-gradient(180deg, var(--panel), var(--bg-2)); padding: 18px; }

/* geometry */
.geo-body { display: grid; grid-template-columns: 1fr 240px; gap: 18px; }
.viewport { height: 520px; border: 1px solid var(--line); border-radius: 3px;
  background: radial-gradient(circle at 50% 40%, #0d141c 0%, #070a0e 100%);
  position: relative; overflow: hidden; }
.geo-side { display: flex; flex-direction: column; gap: 14px; }
.toggle-row { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { appearance: none; font-family: var(--mono); font-size: 11.5px; cursor: pointer;
  background: #0c1017; color: var(--ink-dim); border: 1px solid var(--line-2);
  padding: 7px 11px; border-radius: 999px; transition: all .16s; }
.chip:hover { color: var(--ink); border-color: var(--dark-glow); }
.chip.is-on { color: var(--bg); background: var(--dark); border-color: var(--dark);
  box-shadow: 0 0 14px rgba(53,208,230,0.35); }
.chip.play { min-width: 76px; }
.site-legend { list-style: none; margin: 0; padding: 0; font-size: 12px; }
.site-legend li { display: flex; align-items: center; gap: 9px; padding: 5px 0;
  border-bottom: 1px dashed var(--line); }
.site-legend .dot { width: 10px; height: 10px; border-radius: 50%; flex: none;
  box-shadow: 0 0 8px currentColor; }
.site-legend .res { color: var(--ink-dim); margin-left: auto; }

/* matrices */
.matrices { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; }
.matrices figure { margin: 0; }
.matrices figcaption { font-size: 12px; color: var(--ink-dim); margin-bottom: 10px; }
.heat { display: flex; justify-content: center; }

/* plots */
.plot { width: 100%; }
.dyn-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.embed-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 3px; }

/* toolbar / transport */
.toolbar { display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 14px; margin-bottom: 16px; }
.prep-tabs { display: flex; gap: 5px; flex-wrap: wrap; }
.transport { display: flex; align-items: center; gap: 12px; }
.transport input[type=range] { width: 240px; accent-color: var(--bright); }
#tstamp { color: var(--bright); font-size: 12.5px; min-width: 110px; }

/* axes (d3) */
.axis path, .axis line { stroke: var(--line-2); }
.axis text { fill: var(--ink-dim); font-family: var(--mono); font-size: 10px; }
.gridline { stroke: var(--grid); }
.axis-label { fill: var(--ink-dim); font-size: 10.5px; font-family: var(--mono);
  text-transform: uppercase; letter-spacing: 0.06em; }
.plot-title { fill: var(--ink); font-family: var(--display); font-size: 13px; font-weight: 700; }
.legend-txt { fill: var(--ink-dim); font-family: var(--mono); font-size: 10px; }

/* tooltip */
.tooltip { position: fixed; pointer-events: none; z-index: 1000; opacity: 0;
  background: #060809; border: 1px solid var(--dark-glow); color: var(--ink);
  padding: 7px 10px; border-radius: 3px; font-size: 11.5px; transition: opacity .12s;
  box-shadow: 0 8px 30px rgba(0,0,0,0.6); max-width: 240px; }

/* footer */
.footer { display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap;
  padding: 16px 34px; border-top: 1px solid var(--line); color: var(--ink-dim);
  font-size: 11px; }
#foot-status { color: var(--dark); }

@media (max-width: 900px) {
  .geo-body, .matrices, .dyn-grid { grid-template-columns: 1fr; }
  .embed-grid { grid-template-columns: repeat(2, 1fr); }
  .mast-readout { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  .scanline { display: none; }
  .panel { animation: none; }
  * { transition-duration: 0.01ms !important; }
}

/* ---- Introduction view ---- */
.intro-body { padding: 22px 24px 24px; }
.intro-hero { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 26px; align-items: center; }
.intro-eyebrow { color: var(--dark); font-size: 11px; letter-spacing: .04em; margin: 0 0 10px; }
.intro-lead h3 { font-family: var(--display); font-weight: 700; font-size: 23px; line-height: 1.25;
  margin: 0 0 14px; color: var(--ink); }
.intro-lead p { color: #c3cad6; font-size: 13.5px; line-height: 1.6; margin: 0 0 11px; }
.intro-lead b { color: var(--ink); }
.intro-lead em { color: var(--bright); font-style: normal; }
.intro-concept { border: 1px solid var(--line); border-radius: 5px; padding: 8px;
  background: radial-gradient(circle at 30% 40%, #0d141c, #070a0e); min-height: 220px;
  display: flex; align-items: center; }
#intro-concept text { font-family: var(--mono); }

.intro-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin: 26px 0 8px; }
.intro-card { border: 1px solid var(--line-2); border-left-width: 3px; border-left-color: var(--line-2);
  border-radius: 5px; padding: 14px 15px; background: #0c1017; }
.intro-card.is-bright { border-left-color: var(--bright); }
.intro-card.is-dark { border-left-color: var(--dark); }
.intro-card .ic-k { display: block; font-size: 11px; letter-spacing: .05em; text-transform: uppercase;
  color: var(--ink-dim); margin-bottom: 7px; }
.intro-card.is-bright .ic-k { color: var(--bright); }
.intro-card.is-dark .ic-k { color: var(--dark); }
.intro-card p { margin: 0; font-size: 12.5px; line-height: 1.5; color: #c3cad6; }
.intro-card b { color: var(--ink); }

.intro-h { font-family: var(--display); font-weight: 700; font-size: 18px; margin: 28px 0 4px; color: var(--ink); }
.intro-sub { color: var(--ink-dim); font-size: 12.5px; margin: 0 0 16px; }
.intro-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.intro-step { text-align: left; cursor: pointer; font-family: var(--mono);
  background: #0c1017; border: 1px solid var(--line-2); border-radius: 6px; padding: 13px 14px;
  display: flex; flex-direction: column; gap: 5px; transition: transform .14s, border-color .14s, background .14s; }
.intro-step:hover { transform: translateY(-3px); border-color: var(--dark); background: #0e141d; }
.intro-step .is-n { color: var(--bright); font-size: 12px; }
.intro-step .is-name { font-family: var(--display); font-weight: 700; font-size: 14px; color: var(--ink); }
.intro-step .is-desc { font-size: 11.5px; line-height: 1.45; color: var(--ink-dim); }

.intro-foot { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; margin-top: 26px;
  padding-top: 18px; border-top: 1px solid var(--line); }
.intro-start { font-family: var(--mono); font-size: 13px; cursor: pointer; color: var(--bg);
  background: var(--bright); border: 1px solid var(--bright); border-radius: 999px; padding: 11px 22px;
  box-shadow: 0 6px 22px rgba(255,107,26,.3); transition: transform .15s; }
.intro-start:hover { transform: translateY(-2px); }
.intro-note { margin: 0; color: var(--ink-dim); font-size: 12px; }
.intro-note b { color: var(--bright); }

@media (max-width: 900px) {
  .intro-hero, .intro-cards { grid-template-columns: 1fr; }
  .intro-steps { grid-template-columns: repeat(2, 1fr); }
}
@media (prefers-reduced-motion: reduce) {
  .intro-step, .intro-start { transition: none; }
}

.intro-link { color: var(--dark); text-decoration: none; border-bottom: 1px solid rgba(53,208,230,.4); }
.intro-link:hover { color: var(--bright); border-bottom-color: var(--bright); }