:root {
  color-scheme: dark;
  --bg: #04060d;
  --panel: #0a0f1c;
  --line: #1b2438;
  --text: #e8edf7;
  --muted: #8b96ad;
  --accent: #6ea8ff;
  --btn-bg: #121a2e;
  --btn-border: #273353;
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  overflow: hidden;
}

.app-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  padding: 10px 16px 8px;
}

.app-header h1 {
  margin: 0;
  font-size: 18px;
  font-weight: 650;
  letter-spacing: 0.2px;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 12.5px;
}

.stage {
  flex: 1;
  min-height: 0;
  display: flex;
  padding: 0 16px;
}

.canvas-wrap {
  position: relative;
  flex: 1;
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  background: #03040a;
}

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

.hint {
  position: absolute;
  top: 10px;
  left: 12px;
  max-width: 78%;
  padding: 6px 10px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--muted);
  background: rgba(8, 12, 24, 0.72);
  border: 1px solid var(--line);
  border-radius: 8px;
  pointer-events: none;
}

.hint kbd {
  font-family: inherit;
  font-size: 11px;
  padding: 1px 5px;
  border: 1px solid #2c3a5c;
  border-bottom-width: 2px;
  border-radius: 5px;
  background: #101830;
  color: var(--text);
}

.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  padding: 10px 16px 12px;
  border-top: 1px solid var(--line);
  background: var(--panel);
}

button {
  min-height: 44px;
  padding: 0 16px;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  background: var(--btn-bg);
  border: 1px solid var(--btn-border);
  border-radius: 10px;
  cursor: pointer;
  transition: background 120ms ease, border-color 120ms ease;
}

button:hover {
  background: #18223c;
  border-color: #35436b;
}

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

button:focus-visible,
input[type="range"]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.slider-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.slider-group label {
  font-size: 13px;
  color: var(--muted);
  white-space: nowrap;
}

.slider-group input[type="range"] {
  width: 130px;
  height: 44px;
  accent-color: var(--accent);
  cursor: pointer;
}

.slider-group output {
  font-size: 12.5px;
  color: var(--muted);
  min-width: 46px;
  font-variant-numeric: tabular-nums;
}

.hud {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 12.5px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.hud-item { white-space: nowrap; }

.hud .energy output {
  color: var(--text);
  font-weight: 600;
}

@media (max-width: 700px) {
  .app-header { padding: 8px 12px 6px; gap: 8px; }
  .app-header h1 { font-size: 16px; }
  .subtitle { font-size: 11.5px; }
  .stage { padding: 0 10px; }
  .controls {
    padding: 8px 12px 10px;
    gap: 8px 12px;
  }
  .slider-group { flex: 1 1 45%; }
  .slider-group input[type="range"] { flex: 1; width: auto; min-width: 60px; }
  .hud {
    margin-left: 0;
    width: 100%;
    justify-content: space-between;
    gap: 8px;
    font-size: 11.5px;
  }
}