:root {
  --bg: #05070d;
  --panel: #0b0f1a;
  --panel-edge: #1c2436;
  --text: #d8e6ff;
  --text-dim: #6b7a99;
  --energy: #e9ff2f;
  --crudeOil: #ff2fb0;
  --fuel: #ff8f1f;
  --rawCoal: #9b6bff;
  --coal: #2fe6ff;
  --danger: #ff3b5c;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

#app {
  max-width: 600px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: linear-gradient(180deg, var(--bg) 80%, rgba(5,7,13,0));
  padding: 14px 16px 18px;
  border-bottom: 1px solid var(--panel-edge);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.wordmark {
  margin: 0;
  font-size: 1.15rem;
  letter-spacing: 0.35em;
  font-weight: 700;
  text-align: center;
  color: var(--energy);
  text-shadow: 0 0 6px var(--energy), 0 0 18px rgba(233, 255, 47, 0.4);
}

.grid-panel {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
}

.ring-wrap {
  position: relative;
  width: 64px;
  height: 64px;
  flex: 0 0 auto;
}

.tick-ring {
  width: 64px;
  height: 64px;
  transform: rotate(-90deg);
}

.ring-track {
  fill: none;
  stroke: var(--panel-edge);
  stroke-width: 5;
}

.ring-fill {
  fill: none;
  stroke: var(--energy);
  stroke-width: 5;
  stroke-linecap: round;
  stroke-dasharray: 169.6;
  stroke-dashoffset: 0;
  filter: drop-shadow(0 0 4px var(--energy));
}

.ring-label {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
  color: var(--text);
}

.energy-readout {
  display: flex;
  align-items: center;
  gap: 10px;
}

.energy-icon svg { width: 34px; height: 34px; overflow: visible; }

.energy-caption {
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  color: var(--text-dim);
}

.energy-value {
  font-size: 1.6rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--energy);
  text-shadow: 0 0 8px rgba(233, 255, 47, 0.55);
}

.bar-row { width: 100%; }

.bar-track {
  width: 100%;
  height: 10px;
  border-radius: 6px;
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  overflow: hidden;
}

.bar-fill {
  height: 100%;
  width: 0%;
  border-radius: 6px;
  transition: width 0.6s ease;
}

.energy-fill {
  background: var(--energy);
  box-shadow: 0 0 8px var(--energy);
}

.overclock-btn {
  align-self: center;
}

.card-list {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 18px 16px 40px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  border-radius: 10px;
  padding: 14px 16px 16px;
  width: 100%;
}

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

.card-title {
  margin: 0;
  font-size: 1rem;
  letter-spacing: 0.06em;
  color: var(--text);
}

.card-desc {
  margin: 2px 0 10px;
  font-size: 0.78rem;
  color: var(--text-dim);
}

.card-rate {
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
  color: var(--text-dim);
  white-space: nowrap;
}

.flow-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 6px 0 12px;
}

.flow-icon svg { width: 30px; height: 30px; overflow: visible; flex: 0 0 auto; }

.flow-arrow {
  color: var(--text-dim);
  font-size: 1.1rem;
}

.buffer-block { flex: 1; min-width: 0; }

.buffer-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-bottom: 4px;
}

.buffer-label .resource-name { color: var(--text); }

.upgrades {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 4px;
}

.upgrade-btn {
  flex: 1 1 auto;
  min-width: 120px;
  background: transparent;
  border: 1px solid currentColor;
  color: var(--coal);
  border-radius: 6px;
  padding: 8px 10px;
  font-size: 0.75rem;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.15s ease, box-shadow 0.15s ease;
  text-shadow: 0 0 4px currentColor;
}

.upgrade-btn:hover:not(:disabled) {
  background: rgba(47, 230, 255, 0.08);
  box-shadow: 0 0 10px currentColor;
}

.upgrade-btn:disabled {
  color: var(--text-dim);
  cursor: not-allowed;
  text-shadow: none;
  opacity: 0.6;
}

.overclock-btn {
  color: var(--energy);
}

.footnote {
  text-align: center;
  font-size: 0.68rem;
  color: var(--text-dim);
  padding: 10px 0 24px;
  letter-spacing: 0.08em;
}

@media (min-width: 601px) {
  .wordmark { font-size: 1.4rem; }
  .card { padding: 18px 22px 20px; }
}