:root {
  --bg-primary: #0f172a;
  --bg-card: #1e293b;
  --bg-hover: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #06b6d4;
  --accent-dim: rgba(6, 182, 212, 0.15);
  --border-color: #334155;
  --color-voltage: #22d3ee;
  --color-m: #f97316;
  --color-h: #a855f7;
  --color-n: #22c55e;
  --color-gna: #ef4444;
  --color-gk: #3b82f6;
  --color-phase: #eab308;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
}
.hh-container { max-width: 1400px; margin: 0 auto; padding: 20px; }
header { text-align: center; margin-bottom: 24px; }
header h1 {
  font-size: 1.8rem; font-weight: 700;
  background: linear-gradient(135deg, #22d3ee, #a855f7);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
  margin-bottom: 6px;
}
header .subtitle { color: var(--text-secondary); font-size: 0.95rem; }
.main-layout { display: grid; grid-template-columns: 1fr 320px; gap: 20px; }
@media (max-width: 1024px) { .main-layout { grid-template-columns: 1fr; } }

/* Plots */
.plots-column { display: flex; flex-direction: column; gap: 16px; }
.plot-card {
  background: var(--bg-card); border-radius: 12px;
  border: 1px solid var(--border-color); padding: 16px;
}
.plot-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 10px;
}
.plot-label {
  font-size: 0.85rem; font-weight: 600; color: var(--text-secondary);
  text-transform: uppercase; letter-spacing: 0.05em;
}
.plot-info {
  font-size: 0.78rem; color: var(--accent);
  font-variant-numeric: tabular-nums; font-weight: 600;
}
.plot-wrapper {
  position: relative; width: 100%;
  background: #0a0f1e; border-radius: 8px;
  overflow: hidden;
}
.plot-wrapper canvas {
  width: 100%; height: 100%; display: block;
}
.plot-card:first-child .plot-wrapper {
  height: 200px;
}
.plot-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.plot-card.half .plot-wrapper { height: 180px; }
.plot-card:last-child .plot-wrapper { height: 200px; }

/* Controls */
.controls-column { display: flex; flex-direction: column; gap: 16px; }
.control-card {
  background: var(--bg-card); border-radius: 12px;
  border: 1px solid var(--border-color); padding: 16px;
}
.control-card h3 {
  font-size: 0.85rem; font-weight: 600; color: var(--text-secondary);
  text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 12px;
}

/* Presets */
.preset-grid { display: flex; flex-wrap: wrap; gap: 6px; }
.preset-btn {
  flex: 1 1 calc(50% - 3px); min-width: 0;
  padding: 8px 6px; border-radius: 8px;
  background: var(--bg-primary); border: 1px solid var(--border-color);
  color: var(--text-secondary); font-size: 0.72rem; font-weight: 600;
  cursor: pointer; transition: all 0.2s; text-align: center;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.preset-btn:hover { background: var(--bg-hover); border-color: var(--accent); color: var(--text-primary); }
.preset-btn.active {
  background: var(--accent-dim); border-color: var(--accent);
  color: var(--accent);
}

/* Mode toggle */
.mode-toggle { display: flex; gap: 6px; }
.mode-btn {
  flex: 1; padding: 8px 6px; border-radius: 8px;
  background: var(--bg-primary); border: 1px solid var(--border-color);
  color: var(--text-secondary); font-size: 0.78rem; font-weight: 600;
  cursor: pointer; transition: all 0.2s; text-align: center;
}
.mode-btn:hover { background: var(--bg-hover); border-color: var(--accent); color: var(--text-primary); }
.mode-btn.active {
  background: var(--accent-dim); border-color: var(--accent);
  color: var(--accent);
}

/* Sliders */
.slider-group { margin-bottom: 12px; }
.slider-group:last-child { margin-bottom: 0; }
.slider-label {
  display: flex; justify-content: space-between; align-items: center;
  font-size: 0.78rem; color: var(--text-secondary); margin-bottom: 4px;
}
.slider-label > span:first-child { flex: 1; }
.slider-value {
  font-weight: 600; color: var(--text-primary);
  min-width: 36px; text-align: right; font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
}
.slider-unit {
  font-size: 0.65rem; color: var(--text-muted); min-width: 48px; text-align: right;
}
input[type="range"] {
  width: 100%; height: 5px; -webkit-appearance: none; appearance: none;
  background: var(--bg-primary); border-radius: 3px; outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 14px; height: 14px; border-radius: 50%;
  background: var(--accent); cursor: pointer;
}
input[type="range"]::-moz-range-thumb {
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--accent); cursor: pointer; border: none;
}

/* Buttons */
.btn-group { display: flex; gap: 8px; }
.action-btn {
  flex: 1; padding: 10px; border-radius: 8px; font-size: 0.85rem;
  font-weight: 600; cursor: pointer; transition: all 0.2s;
  border: 1px solid var(--border-color);
  background: var(--bg-card); color: var(--text-secondary);
}
.action-btn:hover { background: var(--bg-hover); color: var(--text-primary); }
.action-btn.primary {
  background: var(--accent-dim); border-color: var(--accent);
  color: var(--accent);
}
.action-btn.primary:hover { background: rgba(6, 182, 212, 0.25); }

/* Stats */
.stats-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.stat-item {
  background: var(--bg-primary); border-radius: 8px;
  padding: 8px; text-align: center;
}
.stat-label { font-size: 0.65rem; color: var(--text-muted); margin-bottom: 2px; }
.stat-value { font-size: 0.9rem; font-weight: 700; font-variant-numeric: tabular-nums; }

/* Explanation */
.explanation {
  background: var(--bg-card); border-radius: 12px;
  border: 1px solid var(--border-color);
  padding: 24px; margin-top: 20px;
}
.explanation h2 { font-size: 1.1rem; margin-bottom: 16px; color: var(--text-primary); }
.explanation p {
  color: var(--text-secondary); font-size: 0.9rem;
  margin-bottom: 12px; line-height: 1.7;
}
.explanation p:last-child { margin-bottom: 0; }

/* Responsive */
@media (max-width: 768px) {
  .hh-container { padding: 12px; }
  header h1 { font-size: 1.3rem; }
  .plot-row { grid-template-columns: 1fr; }
  .plot-card:first-child .plot-wrapper { height: 160px; }
  .plot-card.half .plot-wrapper { height: 150px; }
  .plot-card:last-child .plot-wrapper { height: 160px; }
  .preset-btn { flex: 1 1 calc(33% - 4px); }
}