:root {
  --color-ink: #17212b;
  --color-muted: #687582;
  --color-paper: #f7f8f6;
  --color-surface: #ffffff;
  --color-border: #dce3e4;
  --color-accent: #1d7a70;
  --color-accent-dark: #155c55;
  --color-accent-soft: #dff1ed;
  --color-high: #c85c35;
  --color-low: #8d99a5;
  --color-shadow: rgba(23, 33, 43, 0.08);
  --font-display: Georgia, "Times New Roman", serif;
  --font-body: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --space-1: 0.35rem;
  --space-2: 0.65rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2rem;
  --space-6: 3rem;
  --space-7: 5rem;
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --content-width: 76rem;
}

* {
  box-sizing: border-box;
}

body {
  min-width: 20rem;
  margin: 0;
  color: var(--color-ink);
  background:
    radial-gradient(circle at 90% 0%, rgba(223, 241, 237, 0.85), transparent 28rem),
    var(--color-paper);
  font-family: var(--font-body);
  line-height: 1.5;
}

button {
  font: inherit;
}

.page-shell {
  width: min(calc(100% - 2 * var(--space-4)), var(--content-width));
  margin: 0 auto;
}

.site-header {
  border-bottom: 1px solid rgba(220, 227, 228, 0.8);
  background: rgba(247, 248, 246, 0.85);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 4.5rem;
  gap: var(--space-3);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-ink);
  font-weight: 750;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border-radius: var(--radius-sm);
  color: var(--color-surface);
  background: var(--color-accent);
  font-size: 1.4rem;
}

.iteration-label,
.eyebrow {
  color: var(--color-accent-dark);
  font-size: 0.75rem;
  font-weight: 750;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero {
  max-width: 45rem;
  padding: var(--space-7) 0 var(--space-5);
}

.eyebrow {
  margin: 0 0 var(--space-3);
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  max-width: 38rem;
  margin-bottom: var(--space-3);
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 8vw, 5.5rem);
  font-weight: 500;
  letter-spacing: -0.06em;
  line-height: 0.98;
}

.hero-copy {
  max-width: 39rem;
  margin-bottom: 0;
  color: var(--color-muted);
  font-size: 1.1rem;
}

.legend {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-3) var(--space-4);
  margin-bottom: var(--space-4);
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.58);
  color: var(--color-muted);
  font-size: 0.88rem;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  color: var(--color-ink);
  font-weight: 650;
}

.legend-hint {
  margin-left: auto;
}

.signal-dot {
  display: inline-block;
  width: 0.6rem;
  height: 0.6rem;
  border-radius: 50%;
}

.signal-high {
  background: var(--color-high);
}

.signal-low {
  background: var(--color-low);
}

.gate-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 34rem), 1fr));
  gap: var(--space-4);
  padding-bottom: var(--space-7);
}

.gate-card {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  box-shadow: 0 1rem 2.5rem var(--color-shadow);
}

.gate-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.gate-card h2 {
  margin-bottom: var(--space-1);
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 500;
  letter-spacing: -0.04em;
  line-height: 1;
}

.gate-description {
  margin-bottom: 0;
  color: var(--color-muted);
  font-size: 0.9rem;
}

.gate-symbol {
  flex: 0 0 auto;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  color: var(--color-accent-dark);
  background: var(--color-accent-soft);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 0.8rem;
  font-weight: 700;
}

.gate-demo {
  display: grid;
  grid-template-columns: minmax(5rem, 1fr) minmax(5rem, 1.2fr) minmax(5rem, 1fr);
  align-items: center;
  gap: var(--space-2);
  min-height: 8.5rem;
  margin-bottom: var(--space-4);
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background: #f4f7f6;
}

.signal-stack {
  display: grid;
  gap: var(--space-2);
}

.signal-control {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-muted);
  background: var(--color-surface);
  cursor: pointer;
  font-size: 0.75rem;
  font-weight: 750;
  text-transform: uppercase;
  transition: border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.signal-control:hover {
  border-color: var(--color-accent);
  transform: translateY(-1px);
}

.signal-control:focus-visible {
  outline: 3px solid rgba(29, 122, 112, 0.3);
  outline-offset: 2px;
}

.signal-control[data-value="1"] {
  border-color: rgba(200, 92, 53, 0.45);
  color: var(--color-high);
  box-shadow: inset 0 -2px 0 var(--color-high);
}

.signal-value {
  color: var(--color-ink);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 1.1rem;
}

.gate-visual {
  position: relative;
  display: grid;
  min-height: 5.5rem;
  place-items: center;
  border: 2px solid var(--color-accent);
  border-radius: 40% 55% 55% 40% / 50%;
  color: var(--color-accent-dark);
  background: var(--color-accent-soft);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 1.1rem;
  font-weight: 800;
}

.gate-visual::before,
.gate-visual::after {
  position: absolute;
  top: 50%;
  width: var(--space-2);
  height: 1px;
  background: var(--color-accent);
  content: "";
}

.gate-visual::before {
  right: 100%;
}

.gate-visual::after {
  left: 100%;
}

.gate-output {
  display: grid;
  justify-items: center;
  gap: var(--space-1);
  color: var(--color-muted);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.output-value {
  display: grid;
  width: 3rem;
  height: 3rem;
  place-items: center;
  border: 2px solid var(--color-low);
  border-radius: 50%;
  color: var(--color-low);
  background: var(--color-surface);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 1.35rem;
  font-weight: 800;
}

.output-value[data-value="1"] {
  border-color: var(--color-high);
  color: var(--color-high);
  background: #fff8f4;
}

.table-heading {
  margin: 0 0 var(--space-2);
  color: var(--color-muted);
  font-size: 0.75rem;
  font-weight: 750;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.truth-table {
  width: 100%;
  border-collapse: collapse;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 0.85rem;
}

.truth-table th,
.truth-table td {
  padding: var(--space-2);
  border-bottom: 1px solid #edf0f0;
  text-align: center;
}

.truth-table th {
  color: var(--color-muted);
  font-size: 0.7rem;
  font-weight: 750;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.truth-table tbody tr:last-child td {
  border-bottom: 0;
}

.truth-table tbody tr[data-active="true"] {
  color: var(--color-accent-dark);
  background: var(--color-accent-soft);
  font-weight: 750;
}

.loading-message {
  color: var(--color-muted);
}

.site-footer {
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 0.82rem;
}

.site-footer p {
  margin: var(--space-4) 0;
}

@media (max-width: 40rem) {
  .page-shell {
    width: min(calc(100% - 2 * var(--space-3)), var(--content-width));
  }

  .header-content {
    min-height: 4rem;
  }

  .iteration-label {
    display: none;
  }

  .hero {
    padding-top: var(--space-6);
  }

  .legend-hint {
    flex-basis: 100%;
    margin-left: 0;
  }

  .gate-card {
    padding: var(--space-3);
  }
}