* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #1a1a2e;
  color: #e0e0e0;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
}
h1 {
  margin: 24px 0 12px;
  font-size: 1.6rem;
  font-weight: 600;
  color: #ffffff;
}
#charts {
  display: flex;
  gap: 16px;
  width: 98vw;
}
.chart-panel {
  flex: 1;
  min-width: 0;
  background: #16213e;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.4);
  padding: 12px;
}
.chart-panel h2 {
  margin: 0 0 8px;
  font-size: 1rem;
  font-weight: 600;
  color: #ffffff;
  text-align: center;
}
.chart-panel .chart-container {
  width: 100%;
  height: 78vh;
}
#run-btn, #download-btn {
  margin: 12px 0;
  padding: 10px 24px;
  font-size: 0.95rem;
  font-weight: 600;
  color: #ffffff;
  background: #40c040;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s;
}
#run-btn:hover, #download-btn:hover {
  background: #30a030;
}
#run-btn:disabled, #download-btn:disabled {
  background: #888;
  cursor: not-allowed;
}