:root {
  --bg: #070a10;
  --panel: #0f141e;
  --border: #1d2533;
  --text: #e6edf3;
  --muted: #8b95a5;
  --neon: #39ff14;
  --cyan: #00d9ff;
  --pink: #ff2e63;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(1200px 600px at 50% -10%, #121a28 0%, var(--bg) 60%);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  padding: 24px 20px 48px;
}

header {
  max-width: 1600px;
  margin: 0 auto 24px;
  text-align: center;
}

h1 {
  margin: 0;
  font-size: 1.9rem;
  letter-spacing: -0.02em;
}

h1 .sub {
  display: block;
  font-size: 0.95rem;
  font-weight: 400;
  color: var(--cyan);
  margin-top: 4px;
}

.tagline {
  color: var(--muted);
  max-width: 620px;
  margin: 12px auto 0;
  line-height: 1.5;
}

/* ── layout ──────────────────────────────────────────────── */

main {
  max-width: 1600px;
  margin: 0 auto;
  display: grid;
  /* default: board | stats, info spans full width below */
  grid-template-columns: minmax(0, 480px) minmax(0, 1fr);
  grid-template-rows: auto;
  gap: 24px;
  align-items: start;
}

.info-col {
  grid-column: 1 / -1;
}

.explain-section {
  grid-column: 1 / -1;
}

/* 3-column on wide screens: board | tables | network */
@media (min-width: 1200px) {
  main {
    grid-template-columns: 480px minmax(200px, 320px) minmax(300px, 1fr);
  }

  .info-col {
    grid-column: auto;
  }
}

/* stack on mobile */
@media (max-width: 820px) {
  main {
    grid-template-columns: 1fr;
  }

  .info-col {
    grid-column: 1;
  }
}

/* ── board ───────────────────────────────────────────────── */

#board {
  width: 100%;
  max-width: 480px;
  aspect-ratio: 1 / 1;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #0b0f17;
  box-shadow: 0 0 40px rgba(57, 255, 20, 0.06);
  display: block;
}

/* ── controls ────────────────────────────────────────────── */

.controls {
  margin-top: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 14px;
  align-items: center;
  justify-content: center;
}

button {
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 14px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: border-color 0.15s, transform 0.05s;
}

button:hover {
  border-color: var(--neon);
}

button:active {
  transform: translateY(1px);
}

.ctl {
  font-size: 0.85rem;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.speed {
  display: inline-flex;
  gap: 4px;
}

.speed-btn {
  min-width: 42px;
  font-family: ui-monospace, Menlo, monospace;
}

.speed-btn.selected {
  border-color: var(--neon);
  color: var(--neon);
  box-shadow: 0 0 12px rgba(57, 255, 20, 0.25);
}

.save-status {
  font-size: 0.8rem;
  color: var(--neon);
  opacity: 0;
  transition: opacity 0.3s;
}

input[type="range"] {
  accent-color: var(--neon);
}

input[type="range"]:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

input[type="checkbox"] {
  accent-color: var(--neon);
}

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

/* ── HUD ─────────────────────────────────────────────────── */

.hud {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(88px, 1fr));
  gap: 5px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px 10px;
  margin-bottom: 12px;
}

.hud div {
  display: flex;
  flex-direction: column;
  padding: 4px 6px;
  border-radius: 5px;
  background: rgba(255, 255, 255, 0.015);
}

.hud .k {
  font-size: 0.67rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.hud .v {
  font-family: ui-monospace, Menlo, monospace;
  font-size: 0.95rem;
  color: var(--neon);
}

/* ── charts ──────────────────────────────────────────────── */

.chart {
  width: 100%;
  height: 150px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-bottom: 12px;
  display: block;
}

/* ── hunger meter ────────────────────────────────────────── */

.hunger {
  margin-top: 14px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.hunger-label {
  font-size: 0.82rem;
  color: var(--muted);
}

.hunger-label .muted {
  font-family: ui-monospace, Menlo, monospace;
}

.hunger-track {
  height: 10px;
  background: #11161f;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}

.hunger-fill {
  height: 100%;
  width: 0%;
  background: hsl(120, 90%, 50%);
  transition: width 0.1s linear, background 0.2s linear;
}

.hunger-hint {
  font-size: 0.75rem;
}

/* ── network visualization ───────────────────────────────── */

.net-section h2 {
  margin: 0 0 6px;
  font-size: 1.25rem;
}

.net-caption {
  margin: 0 0 12px;
  line-height: 1.55;
  font-size: 0.88rem;
}

.net-canvas {
  width: 100%;
  height: 340px;
  background: #0b0f17;
  border: 1px solid var(--border);
  border-radius: 12px;
  display: block;
}

/* ── explain ─────────────────────────────────────────────── */

.explain {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 16px;
  font-size: 0.88rem;
  line-height: 1.5;
}

.explain summary {
  cursor: pointer;
  color: var(--cyan);
  font-weight: 600;
}

.explain ol {
  margin: 10px 0;
  padding-left: 20px;
}

.explain li {
  margin-bottom: 10px;
}

footer {
  text-align: center;
  margin-top: 32px;
  font-size: 0.85rem;
}

footer a {
  color: var(--muted);
}

footer a:hover {
  color: var(--neon);
}