:root {
  --bg: #060a12;
  --panel: rgba(15, 23, 34, 0.62);
  --line: rgba(0, 229, 255, 0.16);
  --cyan: #00e5ff;
  --copper: #ff8a3d;
  --trace-green: #39ff88;
  --ink: #dceaf2;
  --ink-dim: #9bafbf;
  color-scheme: dark;
  --mono:
    ui-monospace, 'SFMono-Regular', 'JetBrains Mono', Menlo, Consolas, monospace;
  --sans: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  position: relative;
  overflow-x: hidden;
  padding: 2rem 1rem;
}

/* PCB trace background */
.board-bg {
  position: fixed;
  inset: 0;
  z-index: 0;
  opacity: 0.5;
  pointer-events: none;
}

.board-bg svg {
  width: 100%;
  height: 100%;
}

.flow-dot {
  animation: travel 6s linear infinite;
  filter: drop-shadow(0 0 4px var(--cyan));
}
.flow-dot.d2 {
  animation-delay: -2s;
}
.flow-dot.d3 {
  animation-delay: -4s;
}

@keyframes travel {
  0% {
    offset-distance: 0%;
  }
  100% {
    offset-distance: 100%;
  }
}

.panel {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 880px;
  background: var(--panel);
  backdrop-filter: blur(18px);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 2.75rem 2.5rem 2.25rem;
}

.panel::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 6px;
  padding: 1px;
  background: linear-gradient(
    140deg,
    rgba(0, 229, 255, 0.5),
    transparent 35%,
    rgba(255, 138, 61, 0.35) 85%
  );
  -webkit-mask:
    linear-gradient(#000 0 0) content-box,
    linear-gradient(#000 0 0);
  mask:
    linear-gradient(#000 0 0) content-box,
    linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

.silk-label {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--ink-dim);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1.6rem;
}

.silk-label .pulse {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--trace-green);
  box-shadow: 0 0 8px var(--trace-green);
  animation: blink 1.6s ease-in-out infinite;
  flex-shrink: 0;
}

@keyframes blink {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.35;
  }
}

h1 {
  font-family: var(--sans);
  font-weight: 800;
  font-size: 2.15rem;
  letter-spacing: -0.01em;
  line-height: 1.05;
  margin: 0 0 0.4rem;
  color: #fff;
}

h1 span {
  color: var(--cyan);
}

.subtitle {
  font-size: 0.98rem;
  line-height: 1.55;
  color: var(--ink-dim);
  margin: 0 0 1.9rem;
  max-width: 42ch;
}

.readout {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 4px;
  overflow: hidden;
}

.cell {
  background: rgba(6, 10, 18, 0.7);
  padding: 1rem 0.8rem;
  text-align: left;
  transition: background 0.3s;
}

.cell .k {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  color: var(--ink-dim);
  margin-bottom: 0.35rem;
}

.cell .v {
  font-family: var(--mono);
  font-size: 1.5rem;
  color: var(--trace-green);
  font-variant-numeric: tabular-nums;
}

.cell.warn .v {
  color: var(--copper);
}
.cell.warn {
  background: rgba(255, 138, 61, 0.1);
}

.controls {
  display: flex;
  gap: 8px;
  margin-top: 1.2rem;
}

.controls button {
  flex: 1;
  background: rgba(6, 10, 18, 0.7);
  border: 1px solid var(--line);
  color: var(--ink-dim);
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  padding: 0.65rem 0.4rem;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
}

.controls button:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}

.controls button.active {
  background: rgba(0, 229, 255, 0.1);
  border-color: var(--cyan);
  color: var(--cyan);
  box-shadow: 0 0 8px rgba(0, 229, 255, 0.2);
}

.waveform {
  margin-top: 1.6rem;
  height: 45px;
  width: 100%;
}

.waveform path {
  fill: none;
  stroke: var(--cyan);
  stroke-width: 1.5;
  opacity: 0.85;
  transition: stroke 0.3s;
}

@media (prefers-reduced-motion: reduce) {
  .pulse,
  .flow-dot {
    animation: none;
  }
}

.flow-dot {
  offset-path: path('M -50 120 H 300 V 300 H 850');
}

.flow-dot.d2 {
  offset-path: path('M -50 420 H 220 V 220 H 500 V 500 H 850');
}

.flow-dot.d3 {
  offset-path: path('M -50 60 H 620 V 460 H 850');
}

#fan-val {
  color: var(--cyan);
}

.demo-tag {
  margin-left: auto;
  color: var(--copper);
  letter-spacing: 0.06em;
}
.hint,
.cell p,
details p {
  color: var(--ink-dim);
  font-size: 0.76rem;
  line-height: 1.6;
}
.hint {
  margin: 0.65rem 0 0;
}
.intro-note {
  margin-bottom: 1.5rem;
}
.status-bar {
  display: grid;
  gap: 0.4rem;
  border-left: 3px solid var(--trace-green);
  padding: 0.85rem 1rem;
  background: rgba(57, 255, 136, 0.05);
}
.status-bar strong {
  color: var(--trace-green);
  font: 0.8rem var(--mono);
}
.status-bar > span {
  font-size: 0.78rem;
  color: var(--ink-dim);
}
.status-bar.warn {
  border-color: var(--copper);
  background: rgba(255, 138, 61, 0.07);
}
.status-bar.warn strong {
  color: var(--copper);
}
.section-heading {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.5rem 0 0.85rem;
}
h2 {
  margin: 0;
  font-size: 0.9rem;
  font-weight: 600;
}
.section-heading > span {
  font: 0.65rem var(--mono);
  color: var(--ink-dim);
}

small {
  font-size: 0.66rem;
  color: var(--ink-dim);
  font-weight: normal;
}
.cell p {
  font-size: 0.65rem;
  margin: 0.5rem 0 0;
}
.dashboard-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}
label {
  display: block;
  font-size: 0.72rem;
  color: var(--ink-dim);
  margin-bottom: 0.4rem;
}
select,
button {
  font: 0.72rem var(--mono);
  color: var(--ink);
  background: #0a121d;
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 0.65rem 0.8rem;
  min-height: 44px;
}
select {
  width: 100%;
}
button,
select {
  cursor: pointer;
}
button:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}
button:focus-visible,
select:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.waveform .chart-grid {
  stroke: var(--line);
  stroke-width: 1;
}
.waveform #wave {
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}
.chart-labels {
  display: flex;
  justify-content: space-between;
  color: var(--ink-dim);
  font: 0.62rem var(--mono);
  margin-top: 0.4rem;
}
.session-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.8rem;
  border-block: 1px solid var(--line);
  padding: 1rem 0;
  margin: 0;
}
dt {
  color: var(--ink-dim);
  font-size: 0.72rem;
}
dd {
  font: 1.2rem var(--mono);
  margin: 0.45rem 0 0;
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 1rem;
}
details {
  margin-top: 1.5rem;
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}
summary {
  cursor: pointer;
  font-size: 0.78rem;
  color: var(--ink-dim);
}
footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 1.5rem;
  font: 0.6rem var(--mono);
  color: var(--ink-dim);
}
body.paused .pulse,
body.paused .flow-dot {
  animation-play-state: paused;
}
@media (max-width: 640px) {
  body {
    padding: 1rem 0.6rem;
  }
  .panel {
    padding: 1.5rem 1rem;
  }
  .readout {
    grid-template-columns: repeat(2, 1fr);
  }
  .dashboard-columns {
    grid-template-columns: 1fr;
    gap: 0;
  }
  .controls {
    margin-top: 0;
  }
  .silk-label {
    flex-wrap: wrap;
    font-size: 0.6rem;
    letter-spacing: 0.06em;
  }
  .demo-tag {
    margin-left: 0;
  }
  footer {
    flex-direction: column;
  }
}

[hidden] {
  display: none !important;
}
.source-controls {
  margin: 1rem 0;
}
.source-controls select {
  max-width: 260px;
}
button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Compact pages share a persistent header, navigation and device status. */
.panel {
  padding: 1.6rem 2rem;
}
.silk-label {
  margin-bottom: 1rem;
}
.subtitle {
  margin-bottom: 0;
}
.page-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.5rem;
  margin: 1.25rem 0;
}
.page-nav a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.65rem 0.4rem;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: #0a121d;
  color: var(--ink-dim);
  text-decoration: none;
  font: 0.75rem var(--mono);
}
.page-nav a:hover,
.page-nav a[aria-current='page'] {
  color: var(--cyan);
  border-color: var(--cyan);
  background: rgba(0, 229, 255, 0.08);
}
.page-nav a:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}
.page-title {
  margin-top: 1.25rem;
}
.page-tip {
  margin-top: 1.25rem;
}
#action-note:empty {
  display: none;
}
footer {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}
@media (max-width: 640px) {
  .panel {
    padding: 1.2rem 1rem;
  }
  .page-nav {
    gap: 0.35rem;
    margin: 1rem 0;
  }
  .page-nav a {
    font-size: 0.65rem;
  }
}

@media (min-width: 641px) and (max-height: 850px) {
  body { padding: .8rem 1rem; }
  .panel { padding: 1.2rem 1.8rem; }
  .silk-label { margin-bottom: .65rem; }
  h1 { font-size: 1.9rem; }
  .page-nav { margin: .85rem 0; }
  .status-bar { padding: .65rem .85rem; }
  .section-heading { margin: 1rem 0 .65rem; }
  .waveform { height: 80px; }
  .source-controls { margin: .7rem 0; }
  .intro-note { margin-bottom: .6rem; }
  footer { margin-top: 1rem; padding-top: .7rem; }
}

.welcome-panel {
  max-width: 660px;
  margin-block: max(1rem, calc((100svh - 480px) / 2));
  padding: 2.5rem;
}
.welcome-panel h1 { font-size: clamp(2.2rem, 6vw, 3.2rem); }
.welcome-panel .subtitle { margin-top: .8rem; }
.welcome-description { max-width: 48ch; color: var(--ink-dim); line-height: 1.7; font-size: .9rem; margin: 1.25rem 0 1.75rem; }
.start-button { display: inline-flex; align-items: center; gap: 2rem; color: var(--cyan); border-color: var(--cyan); background: rgba(0,229,255,.08); padding: .9rem 1.2rem; font-size: .85rem; }
.start-button:hover { background: rgba(0,229,255,.16); box-shadow: 0 0 16px rgba(0,229,255,.1); }
.welcome-panel .hint { margin-top: 1rem; }
@media (max-width: 640px) {
  .welcome-panel { padding: 1.75rem 1.25rem; }
  .start-button { width: 100%; justify-content: space-between; }
}