:root {
  --color-bg: #ffffff;
  --color-text: #222222;
  --color-accent: #007acc;
  --color-border: #dddddd;
  --font-base: 'Segoe UI', Tahoma, sans-serif;
  --space-unit: 1rem;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.6;
}

h1, h2, p {
  margin: 0 0 var(--space-unit) 0;
  padding: 0;
}

h1 {
  font-size: 1.8rem;
  font-weight: 600;
  color: var(--color-accent);
}

h2 {
  font-size: 1.4rem;
  font-weight: 500;
}

p {
  font-size: 1rem;
}

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-unit);
  border-bottom: 1px solid var(--color-border);
  background-color: #f5f5f5;
}

.app-footer {
  text-align: center;
  padding: var(--space-unit);
  border-top: 1px solid var(--color-border);
  font-size: 0.9rem;
}

.chart-area {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  padding: var(--space-unit);
  flex: 1;
}

.filter-panel {
  display: flex;
  gap: calc(var(--space-unit) / 2);
  padding: var(--space-unit);
  background-color: #fafafa;
  border-bottom: 1px solid var(--color-border);
}