/*
 * Visual design.
 *
 * The palette is deliberately dark and low-chroma everywhere except the canvas.
 * The simulation itself is the only saturated thing on screen, so the eye goes
 * there first and the explanation reads as annotation rather than competition.
 */

:root {
  color-scheme: dark;

  --surface-void: #05060a;
  --surface-panel: rgba(12, 14, 22, 0.82);
  --surface-raised: rgba(24, 27, 40, 0.9);
  --border-subtle: rgba(140, 160, 210, 0.14);
  --border-strong: rgba(150, 180, 255, 0.32);

  --text-primary: #e8ecf6;
  --text-secondary: #9aa4bd;
  --text-dim: #6b7488;

  --accent-quantum: #6ea8ff;
  --accent-matter: #ff9f45;
  --accent-life: #4ade9b;

  --panel-width: 300px;
  --panel-radius: 14px;
  --font-stack: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", sans-serif;
  --font-mono: "Cascadia Mono", "SF Mono", Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--surface-void);
  color: var(--text-primary);
  font-family: var(--font-stack);
  font-size: 14px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

#simulation-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  cursor: crosshair;
}

/* ---------- Startup overlay ---------- */

.overlay {
  position: fixed;
  inset: 0;
  z-index: 40;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 32px;
  text-align: center;
  background: radial-gradient(circle at 50% 45%, #101426 0%, #04050a 70%);
  transition: opacity 600ms ease, visibility 600ms ease;
}

.overlay h1 {
  margin: 0;
  font-size: 44px;
  font-weight: 200;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  background: linear-gradient(120deg, var(--accent-quantum), var(--accent-life));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.overlay p {
  margin: 0;
  max-width: 46ch;
  color: var(--text-secondary);
}

.overlay-hint {
  font-size: 12px;
  color: var(--text-dim);
}

.overlay.is-hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.overlay.is-error {
  background: radial-gradient(circle at 50% 45%, #2a1015 0%, #080406 70%);
}

/* ---------- Panels ---------- */

.panel {
  position: fixed;
  z-index: 20;
  background: var(--surface-panel);
  backdrop-filter: blur(18px) saturate(140%);
  border: 1px solid var(--border-subtle);
  border-radius: var(--panel-radius);
  transition: opacity 260ms ease, transform 260ms ease;
}

.panel-left {
  top: 16px;
  left: 16px;
  bottom: 168px;
  width: var(--panel-width);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.panel-right {
  top: 16px;
  right: 16px;
  bottom: 168px;
  width: 340px;
  padding: 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.panel-bottom {
  left: 16px;
  right: 16px;
  bottom: 16px;
  height: 140px;
  padding: 14px 18px;
  overflow-x: auto;
  overflow-y: hidden;
}

body.panels-collapsed .panel {
  opacity: 0;
  pointer-events: none;
}

body.panels-collapsed .panel-left {
  transform: translateX(-24px);
}

body.panels-collapsed .panel-right {
  transform: translateX(24px);
}

body.panels-collapsed .panel-bottom {
  transform: translateY(24px);
}

.panel-header {
  padding: 18px 18px 12px;
  border-bottom: 1px solid var(--border-subtle);
}

.brand {
  margin: 0;
  font-size: 19px;
  font-weight: 300;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

.brand-subtitle {
  margin: 2px 0 0;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dim);
}

.panel-footer {
  margin-top: auto;
  padding: 10px 18px;
  border-top: 1px solid var(--border-subtle);
}

.hardware-summary {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-dim);
  overflow-wrap: anywhere;
}

/* ---------- Stage ladder ---------- */

.stage-list {
  flex: 1;
  overflow-y: auto;
  padding: 8px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.stage-button {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  width: 100%;
  padding: 10px 12px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 9px;
  color: var(--text-secondary);
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: background 160ms ease, color 160ms ease, border-color 160ms ease;
}

.stage-button:hover {
  background: var(--surface-raised);
  color: var(--text-primary);
}

.stage-button:focus-visible {
  outline: 2px solid var(--accent-quantum);
  outline-offset: 1px;
}

.stage-button.is-active {
  background: linear-gradient(96deg, rgba(110, 168, 255, 0.18), rgba(110, 168, 255, 0.04));
  border-color: var(--border-strong);
  color: var(--text-primary);
}

.stage-ordinal {
  flex: 0 0 auto;
  padding-top: 1px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
}

.stage-button.is-active .stage-ordinal {
  color: var(--accent-quantum);
}

.stage-text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}

.stage-title {
  font-size: 13px;
  line-height: 1.35;
}

.stage-scale {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-dim);
}

/* ---------- Explanation panel ---------- */

.info-title {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 400;
  line-height: 1.3;
}

.info-section {
  margin: 0 0 8px;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-dim);
}

.info-meta {
  display: flex;
  gap: 8px;
  padding: 3px 0;
  font-size: 11px;
  border-bottom: 1px solid rgba(140, 160, 210, 0.07);
}

.info-meta-key {
  flex: 0 0 52px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 9px;
  padding-top: 2px;
}

.info-meta-value {
  color: var(--text-secondary);
}

.info-summary {
  margin: 14px 0;
  color: var(--text-secondary);
  font-size: 13px;
}

.info-list {
  margin: 0 0 16px;
  padding-left: 16px;
  color: var(--text-secondary);
  font-size: 12.5px;
}

.info-list li {
  margin-bottom: 4px;
}

.info-list li::marker {
  color: var(--accent-life);
}

.info-fidelity {
  margin: 0;
  padding: 10px 12px;
  background: rgba(255, 159, 69, 0.07);
  border-left: 2px solid var(--accent-matter);
  border-radius: 0 7px 7px 0;
  font-size: 11.5px;
  color: var(--text-secondary);
}

/* ---------- Live measurements ---------- */

.info-measurements {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.measurement {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2px 10px;
  padding: 8px 10px;
  background: var(--surface-raised);
  border-radius: 8px;
}

.measurement-label {
  font-size: 11px;
  color: var(--text-secondary);
}

.measurement-value {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-quantum);
  text-align: right;
  white-space: nowrap;
}

.measurement-meaning {
  grid-column: 1 / -1;
  margin: 2px 0 0;
  font-size: 10.5px;
  line-height: 1.45;
  color: var(--text-dim);
}

.measurement-technical .measurement-value {
  color: var(--text-dim);
}

/* ---------- Parameters ---------- */

.parameter-list {
  display: flex;
  gap: 18px;
  height: 100%;
  padding-bottom: 6px;
}

.control-group {
  flex: 0 0 224px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.control-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.control-label {
  font-size: 11.5px;
  color: var(--text-secondary);
}

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

.control-slider {
  width: 100%;
  height: 3px;
  margin: 4px 0;
  appearance: none;
  background: rgba(140, 160, 210, 0.2);
  border-radius: 2px;
  cursor: pointer;
}

.control-slider::-webkit-slider-thumb {
  appearance: none;
  width: 13px;
  height: 13px;
  border: none;
  border-radius: 50%;
  background: var(--accent-quantum);
  cursor: grab;
  box-shadow: 0 0 9px rgba(110, 168, 255, 0.5);
}

.control-slider::-moz-range-thumb {
  width: 13px;
  height: 13px;
  border: none;
  border-radius: 50%;
  background: var(--accent-quantum);
  cursor: grab;
}

.control-slider:focus-visible {
  outline: 2px solid var(--accent-quantum);
  outline-offset: 4px;
}

.control-explanation {
  margin: 0;
  font-size: 10px;
  line-height: 1.4;
  color: var(--text-dim);
}

/* ---------- Transport ---------- */

.transport {
  position: fixed;
  z-index: 25;
  bottom: 168px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  background: var(--surface-panel);
  backdrop-filter: blur(18px);
  border: 1px solid var(--border-subtle);
  border-radius: 999px;
}

.transport-button {
  padding: 5px 14px;
  background: var(--surface-raised);
  border: 1px solid var(--border-subtle);
  border-radius: 999px;
  color: var(--text-secondary);
  font: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: background 150ms ease, color 150ms ease;
}

.transport-button:hover {
  background: rgba(110, 168, 255, 0.16);
  color: var(--text-primary);
}

.transport-button:focus-visible {
  outline: 2px solid var(--accent-quantum);
  outline-offset: 2px;
}

.transport-hint {
  padding-left: 4px;
  font-size: 10.5px;
  color: var(--text-dim);
}

/* ---------- Emergence banner ---------- */

.emergence-banner {
  position: fixed;
  z-index: 30;
  top: 22px;
  left: 50%;
  max-width: 560px;
  padding: 16px 22px;
  transform: translate(-50%, -18px);
  background: linear-gradient(140deg, rgba(74, 222, 155, 0.16), rgba(12, 14, 22, 0.94));
  backdrop-filter: blur(18px);
  border: 1px solid rgba(74, 222, 155, 0.42);
  border-radius: 12px;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 420ms ease, transform 420ms ease, visibility 420ms;
}

.emergence-banner.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translate(-50%, 0);
}

.emergence-banner.is-error {
  background: linear-gradient(140deg, rgba(255, 95, 95, 0.18), rgba(22, 10, 14, 0.94));
  border-color: rgba(255, 95, 95, 0.45);
}

.emergence-banner h3 {
  margin: 0 0 5px;
  font-size: 15px;
  font-weight: 500;
  color: var(--accent-life);
}

.emergence-banner.is-error h3 {
  color: #ff8080;
}

.emergence-banner p {
  margin: 0;
  font-size: 12.5px;
  color: var(--text-secondary);
}

/* ---------- Narrow viewports ---------- */

@media (max-width: 1100px) {
  .panel-right {
    display: none;
  }

  .panel-left {
    width: 240px;
  }
}

@media (max-width: 760px) {
  .panel-left {
    bottom: auto;
    height: 190px;
  }

  .panel-bottom {
    height: 170px;
  }

  .transport {
    bottom: 196px;
  }

  .transport-hint {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .panel,
  .overlay,
  .emergence-banner,
  .stage-button,
  .transport-button {
    transition-duration: 1ms;
  }
}