:root {
  --bg-primary: #070d18;
  --bg-surface: #0e1726;
  --bg-surface-elevated: #142033;
  --border: rgba(255, 255, 255, 0.1);
  --border-focus: #00e5ff;
  --text-primary: #f0f4f8;
  --text-secondary: #8fa3bf;
  --text-muted: #536b88;
  --accent-cyan: #00e5ff;
  --accent-blue: #2979ff;
  --accent-green: #00e676;
  --accent-amber: #ffab00;
  --accent-red: #ff3d71;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  padding: 24px;
}

.sim-container {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.sim-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border);
  padding-bottom: 20px;
}

.sim-title h1 {
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 12px;
}

.sim-title p {
  color: var(--text-secondary);
  font-size: 13px;
  margin-top: 4px;
}

/* Control Panel */
.control-grid {
  display: grid;
  grid-template-columns: 350px 1fr;
  gap: 24px;
}

.panel-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.panel-card h2 {
  font-size: 16px;
  font-weight: 700;
  border-bottom: 1px solid var(--border);
  padding-bottom: 12px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group label {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-secondary);
  text-transform: uppercase;
}

select, input[type="number"], input[type="range"] {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border);
  color: #fff;
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 13px;
  outline: none;
}

.slider-val-wrap {
  display: flex;
  justify-content: space-between;
  font-size: 14px;
  font-weight: 800;
  color: var(--accent-cyan);
}

/* KPI Grid */
.kpi-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.kpi-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}

.kpi-card .label {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-secondary);
  text-transform: uppercase;
}

.kpi-card .value {
  font-size: 26px;
  font-weight: 800;
  color: var(--accent-cyan);
  margin-top: 6px;
}

.kpi-card .subtext {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Cross Section Graphic Box */
.section-box {
  background: #04080f;
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.svg-wrap {
  width: 100%;
  height: 220px;
}

@media (max-width: 1024px) {
  .control-grid {
    grid-template-columns: 1fr;
  }
  .kpi-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .kpi-grid {
    grid-template-columns: 1fr;
  }
}