:root {
  --color-bg: #0a0a0a;
  --color-surface: #1c1c1c;
  --color-accent: #3ac0ff;
  --color-text: #e0e0e0;
  --color-text-muted: #a0a0a0;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --radius-sm: 4px;
  --radius-md: 8px;
  --font-base: system-ui, sans-serif;
  --font-size-base: 1rem;
  --font-size-sm: 0.875rem;
  --layout-header-height: 3.5rem;
  --layout-footer-height: 2.5rem;
}

/* ===================== App Layout ===================== */
.app-shell {
  display: grid;
  grid-template-rows: var(--layout-header-height) 1fr var(--layout-footer-height);
  height: 100vh;
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-base);
  overflow: hidden;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-md);
  background-color: var(--color-surface);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.app-main {
  display: grid;
  grid-template-columns: 1fr 320px;
  overflow: hidden;
}

.app-footer {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-sm);
  background-color: var(--color-surface);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--color-text-muted);
}

/* ===================== Panels ===================== */
.heatmap-panel {
  position: relative;
  background-color: #000;
  overflow: hidden;
}

.stats-panel {
  background-color: var(--color-surface);
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  padding: var(--spacing-md);
  border-left: 1px solid rgba(255, 255, 255, 0.1);
}

/* ===================== Sidebar ===================== */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  overflow-y: auto;
  padding: var(--spacing-md);
}

.sidebar .sidebar__box {
  background-color: rgba(255, 255, 255, 0.05);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
}

.sidebar .sidebar__box + .sidebar__box {
  margin-top: var(--spacing-sm);
}

/* ===================== Responsive ===================== */
@media (max-width: 768px) {
  .app-main {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto;
  }

  .heatmap-panel {
    order: 2;
    height: 50vh;
  }

  .stats-panel {
    order: 1;
    height: auto;
    max-height: 50vh;
  }
}

/* ===================== Footer Copyright ===================== */
.app-footer::after {
  content: '© 2026 Donau2Space.de';
  margin-left: var(--spacing-sm);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}